Does Vaporeon have smooth skin, fur, or scales?

[Red Knight]

This spun off from a post I made in the Random Messages thread that I decided I should make its own thread.

I've always assumed that Vaporeon has smooth, sleek skin like a dolphin. However, I was looking into pinnipeds because I was wondering about the exact mechanics of how Vaporeon might avoid getting sunburn with so much exposed skin and wanted to look at real-world examples, and I found that all pinnipeds except walruses have a fur coat, and even walruses have sparse fur; I'd similarly assumed that at least some seals have little to no fur. And that got me thinking, does Vaporeon actually have smooth skin, or do they have a thin layer of fur like pinnipeds?

On the original post, @da man/man responded:

It looks like it's consistently been sleek dolphin skin.
The only argument you could make for the fur is this:

which might be all the evidence you need tbh

And I would also like to add this:

Spoiler: all of the Eeveelutions side by side

Note how Vaporeon has that light strip on the left side of their tail, as though it's reflecting light, while none of the other Eeveelutions have anything similar on any part of their bodies. This certainly suggests that Vaporeon has a different kind of integument from all the other Eeveelutions (and Pikachu).

For comparison, some images of real world dolphins:

Spoiler: dolphins

From top to bottom: common bottlenose dolphins, a common dolphin, and an orca with calf.

Looking at pictures of seals, though, their fur can also look pretty smooth and glossy, especially when wet:

Spoiler: seals

From top to bottom: a grey seal, a Mediterranean monk seal, and an Australian sea lion with a pup (which likely has not yet molted out of their initial coat). Notably, the adult Mediterranean monk seal is believed to have the shortest fur of any pinniped.

As another argument for Vaporeon having fur, the material the Eevee family drops in ScVi is Eevee Fur. If Vaporeon doesn't have fur, where is the Eevee Fur they drop coming from?

However, this could just be a very minor case of ludonarrative dissonance. Fur makes too much sense as a material for Eevee to drop, since their fluffy tail and mane are such prominent elements of their design while other logical materials like teeth and claws are pretty minor elements of it (in fact, I don't know if their claws have ever been visibly rendered in any of their models), and it makes enough sense for all the other Eeveelutions that the single somewhat illogical case with Vaporeon dropping fur was deemed a worthwhile tradeoff (or perhaps overlooked).

After I presented this second point, @Princess Viola also suggested:

vaporeon is like an otter. smooth fur

I see where this is coming from, but I'm not sure about this particular comparison. Otter fur is a lot more conspicuous, even when wet, perhaps especially when wet. I think if Vaporeon had otter-like fur, it would be a lot more obvious, like on Buizel and Oshawott (and yes, I know Buizel is arguably more weasel than otter, but they're still an aquatic mustelid).

Spoiler: otters

From top to bottom: sea otters, giant otters, and a smooth-coated otter.

Also, some images of fish with various kinds of scales, because you saw the title of the thread and you know I'm going to bring up the possibility of scales:

Spoiler: fish

From top to bottom: Paracanthurus blue tang, sockeye salmon, and West African lungfish.

To check, I decided to boot up ScVi to see what Vaporeon's skin texture looked like up close and compare them it to the other Eeveelutions, and...

Spoiler: ScVi screenshots of Vaporeon and several other species of Pokémon for comparison

There certainly is a texture there! But what is it? Is it skin? Is it thin fur? Is it even, perhaps, fishlike scales? I honestly can't tell.

I also checked Z-A, and Vaporeon's skin is a lot smoother there, but so are the other Eeveelutions'. (For the record, I used the Switch 1 versions of both ScVi and Z-A; maybe they have more detailed textures on the Switch 2 versions, but I don't have a Switch 2, nor do I plan on getting one anytime soon.)

Spoiler: Z-A screenshots

Looking over all the images, I currently still hold that Vaporeon has smooth, hairless skin. But I'd be interested in other's thoughts on the matter.

 

[Ness]

For a long time i thought it had scales but now i think its smooth skin after some random youtube video i watched

I am with the "smooth skin" side not sure about others

 

[da man/man]

Oh shoot! A whole thread on this, nice, I wasn't done researching this yet.

To check, I decided to boot up ScVi to see what Vaporeon's skin texture looked like up close and compare them it to the other Eeveelutions, and...

Spoiler: ScVi screenshots of Vaporeon and several other species of Pokémon for comparison

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There certainly is a texture there! But what is it? Is it skin? Is it thin fur? Is it even, perhaps, fishlike scales? I honestly can't tell.

I also checked Z-A, and Vaporeon's skin is a lot smoother there, but so are the other Eeveelutions'. (For the record, I used the Switch 1 versions of both ScVi and Z-A; maybe they have more detailed textures on the Switch 2 versions, but I don't have a Switch 2, nor do I plan on getting one anytime soon.)

Sooo, maybe it's just me... but Vaporeon in ScVi looks like Rubber? Or a Balloon? It has a clear difference between Finizen's sleek skin, and Floatzels obvious fur, but it doesn't look like scales either. But hear me out though, the rubbery scales look a lot like...

Also, some images of fish with various kinds of scales, because you saw the title of the thread and you know I'm going to bring up the possibility of scales:

Spoiler: fish

From top to bottom: Paracanthurus blue tang, sockeye salmon, and West African lungfish.

The Blue Tang! Take a couple looks between those two, it could just be rubbery scales! NERDY FISH KNOWLEDGE ACTIVATE: Blue Tang are commonly misconcepted to have no scales, but they actually just have incredibly small(borderline invisible) scales that have many ctenii branching off of them

Ctenoid (toothed) scales are like cycloid scales, except they have small teeth or spinules called ctenii along their outer or posterior edges. Because of these teeth, the scales have a rough texture. They are usually found on fishes with spiny fin rays, such as the perch-like fishes.

Ctenii definition ^

This allows the fish to have the appearance of sleek skin, but actually a very rough and spiny texture that you can actually cut yourself!
Another point toward Vaporeon having these small scales, the spine along it's back, which many Blue Tang actually have as well, but can extend and fold vs Vaporeons being out all the time.

Spoiler: The Spine in Question

That looks quite similar to Vaporeon's doesn't it?
These spines are also their poisonous defense mechanism. And what move is Vaporeon commonly displayed using in Pokemon Media? Acid Armor!

I think I've made a decent case, that Vaporeon actually has tiny ctenoid scales, not sleek skin (which the scales are meant to give the illusion of) or fur!

Fish knowledge potentially coming in clutch XD

 

[NumberOneSpinelApologist]

First of all I have to commend that yall are asking the real , fundamental even, questions here.
Second of all, my not so researched take that is somewhat irrelevant: my first intuition would be to say that vaporeon has like you know, mammalian vibes similar to the other eevees? It seems more similar to otters to me than to dolphins at first glance. So I would say it has fur. Fur is important for thermoregulation. But then again, maybe Vaporeons do not get cold that easily? They can use ice type moves too so maybe they do not mind the cold that much? So yeah, I do not know.

 

[CrinkTheBunny]

You're all putting so much thought into this, it's awesome <33

I'd say it's skin like a dolphin!! However I could also see it being fur like seals. Does that mean it would be fluffy when it's dry? I don't rlly know anything about seals lol

 

[WholesomeCryptid]

i've always assumed it to be smooth without really putting much second thought into it, but now that i'm actually thinking about it deeper i think i actually prefer it having a little fur like a seal than just having Eevee go bald when it evolves

 

[da man/man]

You thought was done? NOPE

Spoiler

I went and combed through M22 to find as many clear shots of Vaporeon as I could, since M22 is the ultimate combination between the cartoon/anime Pokemon style and realism. Most of the shots aren't good but...

Spoiler

I think I can make a pretty good argument that this is either blubber, or ctenoid scales.

 

[NumberOneSpinelApologist]

I think you just won this discussion

I think I can make a pretty good argument that this is either blubber, or ctenoid scales

 

[Ghost Diplocaulus]

I personally think it's just really oily fur like a seal's, since to me that'd make the most sense biologically seeing how Vaporeon has an amphibious lifestyle, and fur is actually a very important trait for that seeing how it serves as natural sunscreen and all. Sure, it's given glossy shading, but so is Lugia who canonically has feathers (the Silver Wing item is the feather of a Lugia). Besides, in Scarlet and Violet all the Eeveelutions drop fur when defeated, including Vaporeon, something that wouldn't make sense if it was bare-skinned or scaly.

 

[Red Knight]

Excellent points.

I would like to push back a little on this, though:

These spines are also their poisonous defense mechanism. And what move is Vaporeon commonly displayed using in Pokemon Media? Acid Armor!

Acid Armor's original Japanese name translates to "Liquefy" or "Melt," and is likely only Poison-type because of its association with Grimer and Muk, the only other Pokémon to learn the move in Gen 1, for the same reason that Withdraw, which is just withdrawing into a shell, an action with no inherent association with water, is Water-type because all of its users in Gen 1 were (Slowbro and the Squirtle, Shellder, and Omanyte lines). And, as you say yourself, Vaporeon doesn't seem to have the ability to fold or unfold that dorsal ridge. I think if the designers of Vaporeon were trying to draw a connection to something like the blue tang's venomous spines, Vaporeon would learn something like Poison Sting similar to how Jolteon can learn Pin Missile or Flareon can learn Smog, or they would have gotten Poison Point in Gen 3, or they would have kept Toxic when its distribution was nerfed in Gen 9 like Umbreon did. (Technically Toxic's distribution was first nerfed in BDSP, but I refuse to give that slop any credit. And they made some truly baffling omissions for who learns Toxic - highlights include Grimer and Muk, Vespiquen (who learns it by level up but not TM), Breloom but not Shroomish, Seviper, and the aforementioned Umbreon. Just one of many things that shows how little care and effort ILCA put into those pitiful excuses for remakes.)

But, ultimately, that is a pretty minor nitpick of your argument, and you've made a compelling case for Vaporeon having scales. My biggest hangup is that going from fur to scales is a fairly big structural change, but, like, Vaporeon also spontaneously grow fins and gills. And, ultimately, hair is derived from scales, so going from hair back to scales seems plausible.

I do have to wonder, though, whether the scales would be ctenoid specifically. My impression is any kind of scale structure, if the scales are sized and colored and arranged properly, could achieve the effect of making the skin look smooth. I feel like if Vaporeon had scales that are rough enough to cut you if you rub them the wrong way, that would either be mentioned in the Pokédex or be reflected in gameplay somehow (e.g. through getting the Rough Skin Ability). The Pokédex mentions nothing about their integument in any way (which is why this is a conversation in the first place), and Vaporeon's Abilities are Water Absorb and Hydration, which don't really tell us anything either. (I originally had a really long tangent here about the Abilities, but that ultimately boiled down to "a lot of the mons that get these Abilities probably don't have scales or armor at all but some of them do, so make of that what you will.") Absence of evidence is not necessarily evidence of absence, but I think in this case it at least suggests that if Vaporeon have scales, they probably aren't ctenoid in structure. I also wonder whether the scales would be mineralized at all, or if they would just be keratin.

Also, as a point potentially in favor of smooth skin, while going down the rabbit hole for the Ability tangent, I found that plesiosaurs had smooth, scaleless skin on their bodies, with small wrinkles in order to reduce drag from skin friction. (I'm not going to pretend to understand fluid dynamics well enough to explain how that works.) It could be that the texture on Vaporeon's skin is from similar wrinkles. But! Recent findings show that some plesiosaurs actually had scales specifically on their flippers while still having smooth skin on their bodies! From what I can tell, these scales are hypothesized to have helped protect the flippers as the plesiosaur moved along the seafloor, and possibly had a role in camoflauge and/or structural support. This introduces a similar possiblity for Vaporeon; perhaps some parts of their body are bare skin while others are scales. It's also worth noting that reptiles such as plesiosaurs have their scales grow out of their epidermis, while both fish scales and mammal hair are rooted in the dermis. I'm not sure how, if at all, that difference affects the hydrodynamics of scales, but it is a difference.

Spoiler: putting some earlier images side by side for easier comparison

 

[da man/man]

Acid Armor's original Japanese name translates to "Liquefy" or "Melt," and is likely only Poison-type because of its association with Grimer and Muk, the only other Pokémon to learn the move in Gen 1, for the same reason that Withdraw, which is just withdrawing into a shell, an action with no inherent association with water, is Water-type because all of its users in Gen 1 were (Slowbro and the Squirtle, Shellder, and Omanyte lines). And, as you say yourself, Vaporeon doesn't seem to have the ability to fold or unfold that dorsal ridge. I think if the designers of Vaporeon were trying to draw a connection to something like the blue tang's venomous spines, Vaporeon would learn something like Poison Sting similar to how Jolteon can learn Pin Missile or Flareon can learn Smog, or they would have gotten Poison Point in Gen 3, or they would have kept Toxic when its distribution was nerfed in Gen 9 like Umbreon did. (Technically Toxic's distribution was first nerfed in BDSP, but I refuse to give that slop any credit. And they made some truly baffling omissions for who learns Toxic - highlights include Grimer and Muk, Vespiquen (who learns it by level up but not TM), Breloom but not Shroomish, Seviper, and the aforementioned Umbreon. Just one of many things that shows how little care and effort ILCA put into those pitiful excuses for remakes.)

Acid Armor is admittedly a very small part of my case, but I have half decent reason for it too. In Gen 1, the only 3 Pokemon could learn Acid Armor "Liquefy" Vaporeon, Muk, and Grimer. Just going off of the name Liquefy, that sounds like Water move, and it literally fits Vaporeon's whole power and ability to "dissolve" in water, PERFECTLY. In my mind it was made clearly with Vaporeon in mind, with Muk only being given it as a afterthought, but the combination of Muk learning it, AND Vaporeon's possible connection to poison gives the Poison type more sense, besides it just being a tossup between Water or Poison to fit Vaporeon of Muk better.

But, ultimately, that is a pretty minor nitpick of your argument, and you've made a compelling case for Vaporeon having scales. My biggest hangup is that going from fur to scales is a fairly big structural change, but, like, Vaporeon also spontaneously grow fins and gills. And, ultimately, hair is derived from scales, so going from hair back to scales seems plausible.

This is the biggest difference between Vaporeon and Eevee, but it's Pokedex entry clears this up a little.

Vaporeon underwent a spontaneous mutation and grew fins and gills that allow it to live underwater. This Pokémon has the ability to freely control water.

This Pokedex entry states how drastic of a change the fins and gills are. So I'd assume scales are wouldn't be impossible since the Pokedex draw attention to this in particular. Especially since it evolved to live in water specifically, and scales are typically best for that.

I do have to wonder, though, whether the scales would be ctenoid specifically. My impression is any kind of scale structure, if the scales are sized and colored and arranged properly, could achieve the effect of making the skin look smooth. I feel like if Vaporeon had scales that are rough enough to cut you if you rub them the wrong way, that would either be mentioned in the Pokédex or be reflected in gameplay somehow (e.g. through getting the Rough Skin Ability). The Pokédex mentions nothing about their integument in any way (which is why this is a conversation in the first place), and Vaporeon's Abilities are Water Absorb and Hydration, which don't really tell us anything either. (I originally had a really long tangent here about the Abilities, but that ultimately boiled down to "a lot of the mons that get these Abilities probably don't have scales or armor at all but some of them do, so make of that what you will.") Absence of evidence is not necessarily evidence of absence, but I think in this case it at least suggests that if Vaporeon have scales, they probably aren't ctenoid in structure. I also wonder whether the scales would be mineralized at all, or if they would just be keratin.

The reason I bring up ctenoid scales in particular is because, it's the type of scale that gives off the best illusion of sleek skin, and ctenoid scales would be tiny enough to easily evolve from Eevee's fur. So not every hair has to evolve into a "plate" but a much smaller scale.

Also, as a point potentially in favor of smooth skin, while going down the rabbit hole for the Ability tangent, I found that plesiosaurs had smooth, scaleless skin on their bodies, with small wrinkles in order to reduce drag from skin friction. (I'm not going to pretend to understand fluid dynamics well enough to explain how that works.) It could be that the texture on Vaporeon's skin is from similar wrinkles. But! Recent findings show that some plesiosaurs actually had scales specifically on their flippers while still having smooth skin on their bodies! From what I can tell, these scales are hypothesized to have helped protect the flippers as the plesiosaur moved along the seafloor, and possibly had a role in camoflauge and/or structural support. This introduces a similar possiblity for Vaporeon; perhaps some parts of their body are bare skin while others are scales. It's also worth noting that reptiles such as plesiosaurs have their scales grow out of their epidermis, while both fish scales and mammal hair are rooted in the dermis. I'm not sure how, if at all, that difference affects the hydrodynamics of scales, but it is a difference.

I didn't know that, I'll be real, had to research this a little, and yeah. But!

Spoiler: These pictures are really carrying my argument aren't they XD

If Vaporeon had this going on, wouldn't it's torso section (in the second image) be the smooth part? It's tail and fins would obviously be wrinkled or scaled, but even it's upper body seems to have at least a little bit of this texture carried over to it. I think the plesiosaur style of scales/wrinkles has very real merit to it, but I don't see any difference between its tail or fins vs any other part of it's body.

Side Note: We need more questions like this imo. I love Animal Biology and this is absolutely one of my favorite subjects to discuss, so trying to pinpoint the "finer" details of Pokemon is so fun, by using real animal facts as a base.

 

[Red Knight]

I had a long draft written out here, but I decided to go to sleep and look over it after I woke up. My computer updated while I was asleep, and apparently that erased the draft. So that's great. Maybe it's for the best, though, since I wasn't totally happy with the direction that draft was headed, so maybe starting again from scratch was what I needed to do anyway.

Anyway, first, all of the images of Vaporeon posted here thus far for reference:

Spoiler: Vaporeon images

I'd also like to share something from a September 2018 interview with Ken Sugimori (Pokémon's original lead character designer), Motofumi Fujiwara (the designer who created Eevee, Jolteon, and Flareon), and Atsuko Nishida (the designer who created the other Eeveelutions, including Vaporeon) that I found while looking into Vaporeon's design inspirations. The whole interview is interesting (here's a link), but one bit in particular jumped out at me for the purposes of this discussion:

“Many people, including some of this exhibition’s participants, have their own theories and opinions about what kind of fur or skin texture the Eevees have. As far as their texture, what did you have in mind when you created these Pokemon?”

Nishida: “I don’t think that’s something we thought about when we were designing them. We didn’t design them and think ‘Oh, it’d probably feel like this.'” (laughs)

(Everyone laughs)

“You also have to figure out how to express that with the limitations of the pixel art at the time (laughs)."

So, at least during the original creation process, even Vaporeon's original designer didn't really have a particular answer for our question in mind. Pokémon designs have changed over time, of course, and different media will have small variations in how Pokémon are depicted. Pikachu going from their original rotund design to the slimmer modern one due to the anime's influence is the most famous example, but consider also differences in size between listed Pokédex sizes and the sizes Pokémon are depicted as in the anime (there's a whole page on Bulbapedia listing many of them here), or Piplup having black eyes in the anime until Journeys despite being depicted with blue eyes in other media:

Spoiler: Piplup

Original key art, official artwork from the DP: Galactic Battles DVD boxes, Gen 4 back sprite (it's not very clear in the front sprites)

Or more pertinently, compare Vaporeon's original Red/Green sprite, created by Nishida:

And Sugimori's key art modeled after it:

Spoiler: RG key art

Also, this key art isn't strong evidence one way or another, because pretty much all of the key art from Red and Green had this soft, glossy texture:

Spoiler: more RG key art

And, since I used Lapras as an example here, might as well address some stuff about the plesiosaur comparison. I think the mixed bare skin/scales (or mixed fur/scales, perhaps) is highly unlikely for Vaporeon. First of all:

If Vaporeon had this going on, wouldn't it's torso section (in the second image) be the smooth part? It's tail and fins would obviously be wrinkled or scaled, but even it's upper body seems to have at least a little bit of this texture carried over to it. I think the plesiosaur style of scales/wrinkles has very real merit to it, but I don't see any difference between its tail or fins vs any other part of it's body

I think if any part of Vaporeon had a visibly different texture, it would be the feet and maybe the legs, since those are the parts of Vaporeon's body that would warrant protection in the same vein as a plesiosaur's flippers. But the only place I see a possible difference in texture in either the ScVi images or the M22 images is the dorsal ridge. Secondly, the idea of a mix of wrinkled skin and scaly skin on plesiosaurs comes from a find made earlier this year (February or March 2025), and the idea of scales on plesiosaurs at all was first seriously discussed after a find in 2017, while the first find that suggested smooth skin on plesiosaurs was found in 1880. So I find it unlikely that, if any inspiration was drawn from plesiosaurs during the design process for either Vaporeon itself or the textures for M22 or ScVi, they would have considered that particular possibility. And that's the third thing: though Nessie is probably close enough in the folkloric headspace to mermaids (which Nishida directly stated were an inspiration for Vaporeon's design) for a connection to be drawn, especially given Lapras's existence, the link between Vaporeon as a carnivoran/teleost chimera and plesiosaurs is somewhat thin, all things considered. That isn't to say that comparisons between the two are invalid, not at all, but I find it unlikely that such comparisons were a major factor in the design of Vaporeon or the texture applied to them.

The reason I bring up ctenoid scales in particular is because, it's the type of scale that gives off the best illusion of sleek skin, and ctenoid scales would be tiny enough to easily evolve from Eevee's fur. So not every hair has to evolve into a "plate" but a much smaller scale.

Thinking over it a bit more and doing a bit more research, I think I judged the possibility of ctenoid scales too harshly. They wouldn't necessarily be especially sharp, and looking at their structure...

Spoiler: ctenoid scales

Yeah, I could easily see something like this forming from fur mineralizing and/or further keratinizing during the evolution process. Though I also wonder at the possibility of Vaporeon having cycloid scales, which are similar in structure but less jagged. (Couldn't find any particularly good pictures that showed the structure as clearly while also clearly being cycloid and not ctenoid.)

This Pokedex entry states how drastic of a change the fins and gills are. So I'd assume scales are wouldn't be impossible since the Pokedex draw attention to this in particular. Especially since it evolved to live in water specifically, and scales are typically best for that.

I'm not sure if scales are technically "best" for aquatic life. I'd need to do more research on the subject, but I would think bare skin, fur, and scales all have their pros and cons. Plus, evolution (the Darwinian kind) doesn't necessarily result in the most optimal solutions, just the ones that are good enough to ensure that the organism survives and passes those solutions on. And if we're discussing what kind of integument is most optimal for Vaporeon, I think the fact that they a) are warm-blooded and b) also need to have adaptations for being outside the water should be considered as factors. Which, if anything, might point to retaining some fur as the best solution, since that's what most semi-aquatic mammals have settled on. (Though, of course, this could just be a case of "good enough" arising from mammals already having fur, a limitation that Vaporeon is not necessarily as firmly bound by. Again, they spontaneously grow fins and gills, which I think we can agree is a much more drastic morphological change than hair turning to scales.)

I'd also like to circle back to another potential argument in favor of fur by looking at the Mediterranean monk seal again:

Spoiler: Mediterranean monk seal

Their extremely short fur creates a texture that could be argued to be similar to Vaporeon's texture.

Spoiler: Vaporeon images again for easier comparison

Side Note: We need more questions like this imo. I love Animal Biology and this is absolutely one of my favorite subjects to discuss, so trying to pinpoint the "finer" details of Pokemon is so fun, by using real animal facts as a base.

Same. I have my own ulterior motives for asking these questions: I'm doing some writing, and knowing these kinds of details is helpful for descriptions. Like, if someone strokes a Vaporeon's back, what do they feel? What kind of tactile feedback does a Vaporeon receive across their body via their integument? How does it feel for an Eevee evolving into a Vaporeon as their fur changes to suit their new form? That kind of thing. So I end up asking a lot of these kinds of questions. But these discussions are interesting for their own sake as well. Like I said in the top post, this question first came about for me because I was doing research to try to determine the exact mechanics of how bare skin on a Vaporeon might be protected from UV radiation, and that's not a detail that would come up in a story except maybe to inform a minor detail mentioned in passing.

 

[terashards]

i have nothing to contribute to this thread (other than i like the idea of vaporeon with fur because i want to be able to pet a vaporeon with fur which is not an actual argument for what i think the texture would truly be) but reading over this whole discussion has been fascinating and super interesting and thank you both for writing such long and compelling scientific posts lol
edit: oh yes and i got very excited when vaporeon's original red/green sprite was brought up because i love that sprite so much

 

[Sayer]

For a long time i thought it had scales but now i think its smooth skin after some random youtube video i watched

I am with the "smooth skin" side not sure about others

Same for me! Scales because when I was younger that Pkmn remembering me a Siren

 

[The Silver Gallade]

I think that it's probably smooth skin. For me it's because of the tail, because Vaporeon has a tail fin like a dolphin, and they have smooth skin. Also, they have Water Absorb, and I think scales would keep the water out and the water getting caught in the fur would make it less efficient. I don't really know though, I'm not a biologist.

 

[Red Knight]

I think that it's probably smooth skin. For me it's because of the tail, because Vaporeon has a tail fin like a dolphin, and they have smooth skin. Also, they have Water Absorb, and I think scales would keep the water out and the water getting caught in the fur would make it less efficient. I don't really know though, I'm not a biologist.

The Abilities were something I considered as well. I kind of considered it an inconclusive bit of evidence before - while none of the other Water Absorb mons obviously have fur, and Cacnea/Cacturne and Maractus, Dewpider/Araquanid, and Ogerpon-Wellspring clearly have their own things going on to justify Water Absorb, Chinchou/Lanturn, Volcanion, Dracovish, and Arctovish gave me enough pause to not fully accept it as evidence in favor of Vaporeon having smooth skin. But Chinchou/Lanturn are based on footballfish, which generally don't have scales but more so spines poking out of their skin from what I can tell, and Volcanion is... covered in armor, probably? And also might absorb water through its cannons? I also put way too much stock in what Hydration indicated, but that was even less conclusive than Water Absorb, and the more restrictive of the two Abilities is naturally the more informative.

Arctovish and especially Dracovish are probably the least tenuous evidence against Water Absorb indicating smooth skin on Vaporeon, since their Fossilized Fish component is likely based on Dunkleosteus, specifically its head and thorax, which were covered in thick, bony plates. But that's not quite scales either - for all we know, that armor could be porous enough to allow water in - and whether Dunkleosteus had scales or not is both unknown and irrelevant, since the unarmored parts of whatever fish thing was incorporated into Dracovish and Arctovish appear to have not been preserved well enough to influence their external anatomy much. It could still be that they absorb water through the skin on their bodies, though. In that case, according to Bulbapedia, the Fossilized Dino is likely some kind of plesiosaur which, as discussed above, likely had smooth skin. The Fossilized Drake, however, is likely a stegosaurian, and there is conclusive fossil evidence suggesting at least one species had scales, at least on its legs and feet. But, again, there's an awful lot of guesswork - that's only one part of the body on one species - and there is also conclusive fossil evidence suggesting that at least one species had smooth skin covering its dorsal plates. So... yeah, I don't know.

The structure of the tail implying skin texture is something I hadn't thought about, might be worth looking into. My first instinct is that that isn't the most conclusive evidence either - plenty of fish also have lunate tails - but looking into specifics of whether those species of fish have scales and whether said fish tails are actually comparable in anatomy to Vaporeon's could be an interesting road to go down.

For the record, I'm also currently leaning towards smooth skin at the moment.

 

[Red Knight]

Another potential point against scales: being very pedantic about the semantics of the Hoenn Pokédex entry cited above:

Vaporeon underwent a spontaneous mutation and grew fins and gills that allow it to live underwater. This Pokémon has the ability to freely control water.

It only specifies that Vaporeon grows fins and gills, not scales. But this same semantic argument could be used against bare skin as well; it never specifies that Vaporeon loses its fur, either, thus implying that Vaporeon is still covered in fur. Furthermore, many other Eeveelutions have Dex entries that specify changes to their fur's characteristics and functionality. For instance:

Spoiler

Jolteon:

If it is angered or startled, the fur all over its body bristles like sharp needles that pierce foes.

Its weapons are its 10,000-volt electric attacks and its spiky fur. Its sharp hair can pierce enemies when it bristles.

Its cells generate weak power that is amplified by its fur's static electricity to drop thunderbolts. The bristling fur is made of electrically charged needles.

By storing electricity in its body, it can shoot its bristlelike fur like a barrage of missiles.

Flareon:

It fluffs out its fur collar to cool down its body temperature, which can reach 1,650 degrees.

Flareon's fluffy fur has a functional purpose - it releases heat into the air so that its body does not get excessively hot. This Pokémon's body temperature can rise to a maximum of 1,650 degrees F.

Espeon:

It uses the fine hair that covers its body to sense air currents and predict its enemy's actions.

Its fur has the look and feel of velvet. The orb on its forehead glows when it uses psycho-power.

Its fur is so sensitive, it can sense minute shifts in the air and predict the weather...and its foes' thoughts.

It can instantaneously sense its opponent's movements by feeling air currents with its fine fur.

Glaceon:

As a protective technique, it can completely freeze its fur to make its hairs stand like needles.

It lowers its body heat to freeze its fur. The hairs then become like needles it can fire.

It freezes its fur into icicles, spiky and sharp, and tackles its prey.

We again run into the issue of "absence of evidence is not necessarily evidence of absence," but many of Vaporeon's Dex entires double up on emphasizing its cells' similarity to water molecules and its ability to liquefy and blend into water, something that gives us no evidence one way or another (presumably, even its bones liquefy, which indicates that scales or fur would also be able to liquefy). This could be construed to indicate that Vaporeon still has relatively normal fur... or to indicate that the designers still can't make up their minds as to what this creature is covered with.

And as a counterpoint in favor of scales, to my knowledge, mermaids are usually depicted as having scaly tails, so the fact that Vaporeon is often mistaken for a mermaid, as stated in its RB/LG/Scarlet, Sun, and L:A Pokédex entries, may suggest that Vaporeon also has scales.

It lives close to water. Its long tail is ridged with a fin, which is often mistaken for a mermaid’s.

Its cells are composed of units much like water molecules. It lives close to water and is often mistaken for a mermaid.

Tests show that its cells closely resemble water molecules, which perhaps explains its ability to conceal its form while submerged. I believe the origins of mermaid folklore lie with this Pokémon.

Fairly weak evidence IMO, but evidence nonetheless.

 

[NumberOneSpinelApologist]

or to indicate that the designers still can't make up their minds as to what this creature is covered with.

That is probably the true correct answer.

 

[Ghost Diplocaulus]

And as a counterpoint in favor of scales, to my knowledge, mermaids are usually depicted as having scaly tails, so the fact that Vaporeon is often mistaken for a mermaid, as stated in its RB/LG/Scarlet, Sun, and L:A Pokédex entries, may suggest that Vaporeon also has scales.

To be fair, in real life it is believed that mermaids were inspired by embellished accounts/sightings of manatees, dugongs, and beluga whales, none of which have scales.

 

[Staryu Trek]

I think Vaporeon has tiny, smooth scales. In its artwork you can see that Vaporeon has a shading that's a little brighter than is the case with the other Eeveelutions, implying it has shiny scales.