I only keep 4 - 6 Melanotaenia Sp. in a 55. They are much happier when they can run long distance back and forth and up and down. And add strong current. My 55 has 3 powerheads pushing the water all over and my Turquoise go nuts in the currents. And feed your 'Bows often..they use up alot of energy in all that playfulness.