Under the Sea mod discussion

Hi, I am making a mod called Under the Sea, which, obviously, is an underwater-themed mod. I am looking for ideas, so long as they're within reason and still fit in well with Minecraft. So far I  have added a shark-type creature, crabs, crabmen (?), jellyfish, a mob that was supposed to be lobster but turned out different (name ideas?), a biome that is an ocean down to bedrock, and a few items such as crab shells (used to make Shell Armor, which gives a Thorns-like affect), crab claws (which can be thrown as a weapon), and shark fins (used to make shark fin soup). Please leave suggestions!