I think a pair of german blue rams would be best. Or the german gold ram if you want. When buying rams be carefull because ALOT of german blue rams are mass produced in asia and are injected with horomones to make them get their color faster. The bad part is after that it will wear off and it makes them sterile. Often times like dyed fish they die soon after purchase. So it is best to order them online or if you do see them in a pet shop ask where he got them from. He will probably say they where inmported. Then you ask from where. If he says asia leave. If he got them from a breeder in the U.S. take them before they are gone. If you do decide to get them online email them asking the same questions.