Tank was a bad choice of word...cannon would be more appropriate. Anyway IMO Octillery resembles a weapon much more than Remoraid does, and I would have thought of Remoraid as "just another generic fish" had I never seen Octillery. But if it's the other way around for you then I guess we'll just have to disagree.
Remoraid is part archerfish, part revolver, and part remora. Octillery basically takes the weapon comparison further while completely screwing with the species.
I really HOPE that GameFreak isn't mindless enough to make two unrelated pink heartshaped fishes that nobody likes flavor-wise anyways. I mean, why would anyone (who plays Pokemon) like a dumb looking fish that was shaped like a heart anyways (actually, I'm talking about Luvdisc and not the new Pokemon here, because Luvdisc has NO DETAILS whatsoever, while the new Pokemon has some details to make it less simple and less stupid)? I will be severely disappointed if they aren't related in some way. Although I also think it was kind of weird and dumb to make both Bronzong and Metagross blue Steel/Psychic type Pokemon (I like blue, and I like Steel, but I would have liked some more differences better; I mean, they both even have red eyes (although Bronzor doesn't, to be fair)).
EDIT: I don't mean that Bronzong and Metagross aren't different (when I got a closer comparison, I realized they were very different). But the fact that neither Steel nor Psychic is represented by blue, but two of the three final evos that are those types are makes me want them to be farther apart in color. Anyways, Metagross would look badass in a darker blue, and Bronzong's Pokedex says it's green, so enhancing the green would be good. Although, this shouldn't be done now (this should have been done before they were released). I think I will put some sprites up here of the dark-blue Metagross and the green-blue Bronzong, lol.
Talk about digression, XD.
Metagross is based on...something. Either way, it's cool.
Bronzong and its prevo, Bronzor, are nearly straight-ripped from a weird Japanese legend involving a bronze mirror.