I have two. Did not know what they were till I saw this posting, so thankyou. They are skittish. They dont bother any of my small fish, IE barbs, gourami'. They are in a 100 gallon tank with 30 other fish. ( Balas, baby ID,) I do make sure they eat when feeding the group. They have learned that I will put in a certain spot just for them until they are done. Mine do not fight between themselves. Not sure about more than two but you can always try. I would not reccomend buying some now and more later. That might cause territory problems. Pick a number and keep fingers crossed. I have not seen them in Canadian LFS for a long time.