As a child I saw some of this movie on the tv, just before going somewhere with my family. I never got the ending and it has been bothering me my whole life!
I can't really remember my age, but it must have been somewhere between 1998 and 2004, which is why I assume it is a cartoon from the 90's - the style was very fitting with that.
So, it was a 90's cartoon aimed at (young) adults, probably sci-fi genre.. What I remember was these sea creatures and humans fighting each other. I think the humans at some point were in some underwater base, when they got attacked.
The sea-creatures are mostly female and had somewhat human form (with legs), but their bodies were all white and they had green hair. I particularly remember this scene:
A young human man and woman stand by a water, when a somewhat underwater tank appears. Out falls this female sea-creature, gasping. The boy (red/orange hair) approaches the creature, but suddenly the woman draws a gun and aims at the sea creature (she says something like "Freeze" or I don't know. I was a child, and English are not my first language).
The boy says wait and carefully pick up the gasping sea creature and carries her. The sea creature suddenly bites him in the arm, but he proceeds and release her to the ocean.
Later you see the boy sit and stroke his arm at the bitemark.
I also remember that there was this weird 'leader' or something for the sea creature, which had a dark shade and looked a little like Hubba the hut (well, in my head)
So, any ideas?