Magic, My horn sharks are in a tank by themselves. I have read reports where aggresive fish can pick at the eyes of the sharks, so you don't want to keep them with triggers or even damsels. Non-aggresive fish should be okay. No, the sharks don't hide a lot, athough I don't have a ton of live rock. They do like to poke their heads under a crevice or cave, so I do give them some cover so they can feel secure. The main diet for my horns is squid which they love. I also give bits of shrimp, clams, and frozen silversides. Do NOT feed them goldfish. I have a source in Ca. that can get me as many horns as I need for 50. each, but I had to ask you sine you said they were free and easy where you live. I would love to be able to catch legal leopards (36"+) and horns, but I am stuck with Sandbars and dogfish. If I travel south about 500 miles I can get Sharpnose and bonnetheads. In order to ship you use large double bags with enough water to cover the fish and fill the bags with oxygen from an o2 tank. Secure the bags in a styro box and ship overnight first delivery or airport to airport. I am not an expert on Ca. fish regulations, since I don't live there, but for you to keep legally caught fish I would think it would be okay. Of course to catch and sell large quantities you might need more than a fishing license so the gov. will get a cut. Horn sharks are great aquarium fish if you give them a good size tank and good water conditions and care. They can live a couple of decades in a tank.