Howdy,
Jp is absolutely right and it has landed people in the emergency room. (Like the woman who drank 10 bottles of 5 hour energy per day for two weeks! It was not the active ingredient that caused harm, but the added vitamin) Or worse, people died. Best example are early arctic explorers who thought polar bear liver was a treat. They died of acute Vit A poisoning. Animals are no different: the dose makes the poison. For fish, acute lethality across species and vitamins lies around 1 gram per liter.
I have no clue why you were asking this, but I hope this helps.
HarleyK