From Creatures Wikia
The Neptune Ettins are another grendel hunting ettin breed by Grendel Man. They are diffrent from Susano Ettins because they were meant to be aquatic. They are amphibious, and swim with the swimmeragent included with the Aquanorns. They feel homesick for cold areas. When cold, they are not homesick. They hunt down grendels when angry, bored, or crowded. They are tougher to kill then nroaml ettins, and aren't shy about hitting. They also have a lesser instinct for playing with toys if bored. Adults tend to steal eggs and swim off with them. This is meant to prevent grendels from stealing them. Fear turns to anger. Designed for Aquatilis Caverna V2, they are not exclusive carnivores, and were also made to "feast upon the plague" of the overpopulated Water Weedgrass and Bulb Plants. They use the sprites of the Sea Ettins and (like most of the ettin breeds by Grendel Man) the Guppy Ettins.
Neptune Ettins can be downloaded from Grendel Man's section at Creatures @ CU7.