suggestion: read the threads we post in here and look at all the pics. a nano tank is a tank that ranges in sizes from 30 gallons to .5 gallons (i personally think the limit is 20 gallons and below, but many will argue with that theory). they are usually full blown reef tanks with LR, LS, corals, inverts and fish. basically a mini reef. we try the impossible and make it possible. look at the pics in this forum and you will become educated.