I have 10 exodons in a 55 gal, and they seem to be a slow-growing species. I've had them for a few months and they're still pretty small. I feed them TetraColor Tropical flakes 2-3 times a day and every once in a while I'll throw in a bag of guppies or a bag of ghost shrimp.
They have a pictus cat and a rainbow shark as tankmates. I tried adding a chinese algea eater, but he's been MIA for about a month. I'm guessing he didn't make it.
I have one cave for the shark, three plants, and one fake plant.
Normally, the exodons are all spread out and doing their own thing. But when they're spooked, or when they think it's feeding time, they school really tight, it almost makes the tank look empty. And they tear through a bag of live food in 30 seconds or less. They're really fast swimmers, and always hungry.