I love this picture, if only because it shows off all the squid characters so well. Well, Zoidberg isn't a squid or a cephlapod. I guess you were just looking for deep sea invertabrates and you got that right! I was able to recognize all of these except for Molluck. I don't think I've ever even heard of Oddworld before.
The design does look kind of familiar. I guess it would have been better if they were all the same species. Squids and octopi (?) are mollusks and crabs are crustaceans. Everything is just so wonderfully colorful here. You really do seem to be a good artist judging from just this.