The Twili Gang as merfolk! (Yes it is Link's beast mode)
Also since moray eels have two set of jaws and teeth Zant was born to be a moray because... Creepy mouth. And since moray are living in coral reefs it is also an excuse to instead make him live in his giant helm like in his boss battle.
Kinda looks like a SpongeBob house now that I think of it but oh well.