I had a lawnmower goby, an engineer goby, 3 chromis, a clown and a yellow clown goby in a 6 gal nano tank for 2 years before I moved up to a 29 gal tank. They all did fine. Used an HOB filter and an Undergravel filter on 1/2 of the tank. (Cycles the tank in about 3 days) . Used live sand and a live rock (Mixed feeling...fought aiptasia until I found a couple of peppermint shrimp). Just go slowly so your tank can adapt in time and do a water change weekly. (Remember, only 1 gal is a little more than 20% considering sand and rock work).. The corals grew very well but remember to feed and add supplements carefully cuz things get depleted quickly in that small a tank. Please remember...GO SLOWLY AND TEST FREQUENTLY! In spite of the naysayers it can be done. Just think of the fish. The LFS had a tomato clown for more than 4 months. Always stayed in the upper right rear corner and never moved. They then lowered the price to $10. After another month it was still there! I thought WTHeck, can't let this pass and took it home. After a year...it still sits in the same right upper rear corner and won't move more than 2" for a piece of food. Does this fish need a 50 gal tank? Take a 3" tang, is 50 gal good enough for him? maybe not , he wants to swim all over heck and gone. There's something for every situation, just figure it out....that's what's fun about the hobby.
