nah ALL the Inklings and Octolings die in water

We can tell that this Octo is an Octoling instead of an Octarian, since we can see that the tentacles aren’t rounded and their head is shorter. We can also prove this since the piece of tentacle was clearly smaller than the picture—Octolings have smaller tentacles than Octarians—Octarians also aren’t able to change into Octo form, or at least they don’t throughout Octo Valley and Octo Canyon

It’s clearly an Octoling, even the small tentacle is the standard palette—so it’s not a sanitized Octoling, as we see in the Deepsea Metro, Agent 8 dies in water

Eh, it’s probably ink
wait
Nah, ink doesn’t have that kind of wrinkle property