Thanks for your feedback! I will add that to the tutorial as an update after the jam voting period.
The shoal moves away from: dolphins, sharks, anglerfishes and squids. They try to survive
They died because they didn't eat nothing for a long time.
Ah, I see. That all makes sense now that you explained it, but it was completely lost on me when actually playing it. I reckon all of that information should be in the tutorial.