ya then u could breed them and have babysGet something smaller like Guppies or Neon Tetras.. If you want convicts then get a female. One female.
they won't get that big if they are breeding. they do get 6 inches for each species but that's in a large tank(ie. plenty of water changes for small tanks) or in a non-breeding situation. energy for growth is diverted to breeding & defending the brood. I agree though one male of either species will fill that tank. actually only rams or the lamprologus (african) shelldwellers will fit as a pr. as they stay about 3 inches.I wouldn't do it, if you want to start your brother out on fish start him out on something smaller. Male convicts get around 6", females 4" and firemouths also between 4-6". That's far to large. Plus, you have to add the bioload of any fry to produce, and that's if they don't kill eatchother first.
Get something smaller like Guppies or Neon Tetras.. If you want convicts then get a female. One female.