Sunfish are huge monsters that live in the ocean. Most of the beast’s names refer to its flat, roundish shape with its Latin name a word for millstone. It can often be seen basking near the surface, lying on its side. They’re bigger than a bull and weigh about as much too. Despite this they’re actually pretty benign towards humans because their diet consists mainly of jellyfish. Which I thoroughly approve having once found myself in the middle of a whole huge raft of the little buggers. Especially since they eat them in droves because they’re not very nutritious. But I’m digressing. The sunfish in turn are prey to hardly anything although some countries, like Japan, consider them a delicacy.
Unlike many other bony fish the sunfish completely lack a swim bladder. Their flesh may or may not be poisonous with tetrodotoxin, the same thing you get in blowfish, but the sources don’t seem to agree whether this is actually the case. Also, technically they only have one fin because their dorsal and anal fins have merged.