I have a few suggestions for water:
crocodile (doesnt do a lot of damage per bite,but its special thing is what makes it good:trapjaw (bites very very very fast))
alligator (not as strong as the crocodile,but it is much faster then it.it also has trapjaw)
Gator King (stronger then the crocodile,but is slower then it.it has super trapjaw (it bites faster then regular trapjaw by a lot)and it has another special thing:king of gators (spawns alligators and crocodiles every few seconds)
hope you guys like it.