Need help finding and old computer game, see if anyone can help me find it.

Ok, for some reason I just remembered a computer game i use to play when i was younger about surviving the ocean as one of many playable sea creatures and avoid or eat other creatures or plants. You can play a different sharks and be at the top of the food chain or be a small fish, and anyone help me find this game I'm talking about, someone must of played it. Thanks.