i have one of these. great fish. mine is about 6" right now and i feed it on chopped red wiggler earthworms. they get cut (with scissors, dont try a knife) into about 1 cm long segments for easy swallowing since peacocks dont really seem to chew their food, they just kinda choke it down. a tip with live earthworms, if you buy them in one of those plastic tub containers it helps if you store it upside down - with the lid on of course lol - this way when you go to find one you can flip it rightside up and all your earthworms will be on top waiting for you ~ they gather near the "bottom" so it can be very hard to find them sometimes
sand is an absolute must. no getting around that.
cover the top of the tank as they can very easily escape. mine used to do this thing during eating where he would ram himself at high speeds into the glass top on the tank he's now in. very strange, but point made, if there hadnt been a top that fish would have gone flying!
i wouldnt recommend cichlids unless it was something really peaceful like rams. one of my friends keeps SA cichlids and i know how mean and brutish those suckers are. try it if you like, its your fish, but i thought i should mention that.
goodluck, they are great fish. oh and for tank size i recommend 36"l x 12"w as an absolute bare minimum... period. i am upgrading mine to a 48"l x 12.5"w to keep it in for the rest of its life, as far as i know right now anyway. they are great fish, enjoy, oh and this is one of the few spiny eels that actually like the company of its own kind so you could get a few more