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Stalkers would essentially be the same as bonesharks?

Sea dragon: Fireballs
Sea Emperor: Telepathy
Peeper: Wider vision
Bladderfish: extra air sacks for emergency O2
Crabsquid: knocking out electricity whenever you want to to create annoyances for yourself. Yay!

Crashfish DNA should give you the ability to make yourself explode, blowing up the reaper that's about to kill you, but with you also dying in the process.

Gasopod DNA would actually make you fart out poison