if he's still really small (which by the looks of it he is) you can hatch BBS shrimp to feed him. Adult BS have no nutritional value to horses though...just like junkfood basically...and copepods definitely. My horses all spend all day nosing in and around cracks of the rocks for those guys, but you'd have to add them almost daily b/c my horses depleted my pod population in nearly a week and a half..and they're in a 45gal hex...My concern is that if it is an H. Reidi, he'll outgrow that tank before long. swimming space-wise..they're supposed to have 2-3 times the height of their uncurled bodies for a tank.