Q. I have grown several tinfoil barbs to 6 to 7 inches and would like to breed these fish, but I cannot find any literature concerning breeding them. I have heard that these fish cannot be bred in captivity.
A. The tinfoil barb, Barbus schwanefeldi, is a very large species that does not make a particularly good aquarium inhabitant. By very large, I mean that your 6- to 7-inch fish are only about half the length that they normally attain. They do not seem to reach sexual maturity until they are somewhat more than two years old — they should be over 10 inches in length by that time.
Sexing younger fish does not appear to be possible, and mature fish can only be sexed by the extra girth of the egg-laden females. I have not noticed any color differences between the sexes. They can be bred, but they spawn similar to all other barbs or egg-scattering cyprinids, which means that they need considerable space for the courtship and actual breeding. I know of one semi-successful spawning in an 8-foot-long, 360-gallon aquarium, and another successful spawning in a 1200-gallon aquarium, both of which are a little large for the average home aquarist to devote to a single species. If I was ever tempted to try to breed this fish, I think I would do it in an outdoor pond instead of in an aquarium.