Most of the fish that went belly up were sardines.
It took crews from several different cities plus 700 volunteers to clean up the mess. Together they removed 140 tons of dead fish.
Most of the fish were taken to a composting center where they will be turned into fertilizer.
Marine biologists blame the deaths on a critically low level of oxygen in the water which caused the sardines to suffocate.
A USC biologist reported finding high levels of a powerful nerve toxin in the dead fish. The biologist said Domoic acid may explain why the fish crowded in the marina. The toxin has been linked to neurological disorders, illnesses and deaths in other sea life.