i have a small school of females in my 29 gallon community tank and they generally do fine. i also have a halfmoon plekat (sp?) male in a small 2 gallon kritter keeper within the tank resting along the inner rim so it stays at the surface. he can still see the other fish but can't get to them and it seems to work quite well. i keep a small airator in there (for water movement), a few fake plants and a blue mystery snail to help keep thing clean. i just have to make sure the water level in there is a bit higher than the rest of the tank so it's heavy enough not to float away or turn over the setup works very well.