Question of the Month

tends to favour fish that mature quickly, primarily because the sooner a fish reaches a sellable size, the sooner the fish breeder gets a return on his or her investment. All well and good, but it does mean we tend to see fish that are genetically programmed to be smaller and shorter-lived than might be the case in the wild. Add to that the effects of inbreeding, which makes, for example, farmed Betta rather prone to tumours, and the lifespan of domesticated tropical fish varieties is often very difficult to compare with what’s seen with wild-caught members of the same species.

About the best thing we can do is highlight those species that are hard-wired to be annual fish (as with some of the killifish) so that prospective purchasers understand that a breeding colony is the aim with these. Beyond that, there are very few species that cannot be expected to live at least a few years, with fish like tetras and barbs generally living 3-7 years; average-sized cichlids like Angelfish around 10 years; and the larger L-number catfish well over 20 years and potentially 50+ years. But these are all ballpark figures; it’s really difficult to make firm predictions, especially when comparing a domesticated fish with a wild-caught one.