A promotional body is in hot water over the death of goldfish intended to entice business to South Australia.

Advantage SA sent 55 goldfish as part of an invitation to media buyers, urging them to come to Adelaide and "test the water and be the big fish in a small pond".

Advantage SA said some of the fish later died.

But Advantage SA chief Karen Raffen insists they all arrived alive and healthy, with six months' worth of food, after being hand delivered.

She said they would find good homes for any unwanted fish.