THE SUNFISH

The sunfish is a large, oddly shaped fish that gets its name from its habit of floating on its side at the sea surface, warming itself in the sun. This species has no tail and swims with its very large dorsal and anal fins. It is the heaviest bony fish in the world, reaching up to 2300 kg, and the distance from the top of the dorsal to the bottom of the anal fin can be as much as 4 metres.

Sunfish are foraging predators that will eat a variety of food, but their preferred prey are jellyfishes. Jellyfishes are almost exclusively made up of water and are low in calories/nutrients, so a fish with a body as large as the sunfish’s has to eat a whole lot of jellyfishes to support its weight. They have a surprisingly high growth rate and can gain hundreds of pounds in a year, so these jellyfish specialists are always on the hunt. Adults are too large to be threatened by any but the absolute largest potential predators, but medium-sized individuals are eaten by sea lions, killer whales, and large sharks. California sea lions are known to bite the fins off of small ocean sunfish and then play with them like frisbees!