Maybe adding a shark like creature. This shark could be a predator of the sea.The shark would be the size of a Nicheling and would be extremely aggressive . They would look mostly like a hammer head shark with a little changing. Some tentacles, different pattern and/or colour depending on biome and extra finns or tails might be some good ideas. I originally thought they would be silver and blue with some sandy details.They would have 1 defence (from hard skin), 4 fishing, 3 swimming and 2 attack. When killed they give 8 meat. A good name might be Tegrahead or Shasqui.The spawning would be randomly generated just like the blue birds. Maybe a little more often. They tend to be mostly alone and not in school and live about 25 days.
I am not that good at art but I might try my hand at a concept art for these fellas. I am really sorry if I took someone's idea but this is my first time here and I have not yet seen something like this before. This is just a base idea so as time goes on I will add more to this.