They are great fish, I had one a while back but the damn thing had some kind of accident with my filter and broke its back had to be euthanized
Anywho, it probably wouldn't do well with Silver Dollars or Cichlids, because they aren't fast enough to compete for food. They swim with their pectoral fins and are stalking predators, so they take a long time to even approach their food. Mine used to get outcompeted by my Loaches. And you really shouldn't keep more than one, they are Anabantoids... same family as Bettas and Gouramis... so they are pretty agressive towards eachother.