Nothing will really happen, they are not toxic and exotic fish like puffer fish, boxfish fish, blow fish and giant moray eels. Eating parts of their skin or the meat inside can poison our systems and prove fatal if not prepared and cooked right.
As far as the other fish, crustaceans and so fourth, if all prepared properly most can be eaten raw nothing should happen if you eat them. If they are found dead days later they become bacterial bombs and will poison anyone that tries eating them.
The exception to this is food allergies, if your allergic and eat them then an anaphylactic reaction can happen you may stop breathing and then you’ll die.
· 4 months ago