keeping a mandarin in a small tank can be done, but requires effort on your part. they eat live pods, but you can set up a refugium with pods, or order some from ipsf.com, and feed them. this can get expensive, but can keep a mandarin happy. don't get one just to throw it in the tank and let it go, but if you are determined and lucky enough, you can do it in my opinion. alot of folks disagree for various reasons, and most are good, but this crap about leaving them in the wild is pointless. fish stores have the responsibility of not ordering them to sell to people, and as long as they do they will keep doing this.
member bashing because they have a mandarin is stupid. go bash your fish store if you really have a problem with this. imo.