Probably not. Hell terrain will probably see a change in the distant future anyways, so it will no longer be necessary to have hell versions of every terrain.
i changed the shallows terrain:
Spoiler :![]()
it looks less hellish, but on the other hand it looks more in accord with the other hell terrains and it is easier on the eye.
i will put the fire/lava effects not into the terrain, but into features and improvements.
this fish in your example should change into a corrupted resource, something nasty like a piranha or a kraken


Honestly, why don't change water resources when adjacent to hellish terrain?