Concerning the mandarin -
I thought I'd put one in my 30 gal, because this one was tankraised - handraised, really - and would eat from an eyedropper in my hand. Despite all my rules about 'The tank is the pet, not any particular creature in it" and 'fish loss is inevitable' I got very attached to my little mandarin. Every morning before work I fed him, and every evening too, PLUS keeping a rediculously expensive amount of copepods in the refugium and in the tank itself and cycling bacteria to up the level of sand-food. One morning he did not seem to respond to the dropper; I think I fed him before he was out of his mucus sleeping bag. In fact, I think I choked him by getting the food into his gills. That evening he was missing, and I disassembled tthe tank to find him lying dead in one of the caves, with his hummingbird-like side fins folded over his belly, looking so little like a dead fish and so much like a dead puppy or baby that I was actually reduced to tears.
I spent hundreds of dollars in the two months I kept him, between the price of a tank-raised mandarin and the price of all the copepods (which all the other fish eat more quickly than a mandarin can get to them) and the time and the misery . . .
I wouldn't recommend doing that to yourself, Cheeser. They are too special a creature to take on the one chance in 20 it will live 6 months. In a really big, established reef tank where they can live naturally on clumps of substrate bacteria and zooplankton, I'd make one the prize of my tank. But in a little tank, artificially fed - it's too depressing. Sorry.
