Modelengine mobs:
Whale shark:
peaceful animal, ambient large whale
Dolphin:
hunts all small fish, demands food if you hold salmon in your hand
Manta ray:
peaceful animal, ambient creature, will give you a short ride

Single Entity Item Mobs:(all of these are usable as statues and trophies)
Roosterfish:
creates line schools following each other
Sardine
form groups holding tightly together, changes model on less fish each hit
Green sea turtle
peaceful animal, hunts only jellyfish
Pacific nettle jellyfish
hunts small and medium fish that come too close, stings
Mahi mahi
fast predator, hunts small and medium fish
Fiddler crab
seabed animal, salvages corpses
Hermit crab
ambient seabed animal, food for others
Pearl oyster
seabed creature, has 4 pearl colours, can be harvested when open

Loot items:
small, large and medium fish meat
potent venom
whale meat
crab meat
pincer
white, pink, peach and black pearls