10 Impressive Tips To Survive A Shipwreck
Simply put: do not eat any form of jellyfish or any type of fish that has spikes. Continuing with that same trend, avoid fish that have parrot-like beaks or that puff up like balloons, as these are dangerous or deadly.
If you really need to face off against a fish of some kind, or perhaps require some sustenance, then pressing on the eyes of a fish will paralyze them for a short period of time. If you can manage this, then you can have food for quite some time.