For years I have watched people offer standard fin bristlenose for sale to people, stating that these fish carried a gene for longfin. I felt very bad for the people wasting their money and worse wasting the next year or two raising and breeding these standard bristlenose just to find out that all of the babies would look just like mom and dad. As recently as last week we received a call from a customer wanting to place an order for some standard fin, or "normal" super-red bristlenose that carry the longfin gene. It is an understandable mistake to think that the gene that is responsible for the longfin trait might be recessive, but this misunderstanding has been going on far too long now.
We are primarily known for our work with angelfish since we have worked with the longfins or veil tails in angels since the 1970s. It is well known and has been for years, that the gene responsible for veil tail in angelfish is dominant. In other words, if the fish carries a gene for longfin, it will be a longfin. An article written in 1982 for FAMA magazine by Joanne Norton described the veil tail gene as follows: Veil tail in angelfish is due to an autosomal (not on a sex chromosome) dominant gene (Sterba). A double dose of the gene for veil tail results in a very long, droopy tail. The double-dose veil tail is smaller and less vigorous than the single-dose veil tail and is not a prolific breeder. A mating in which both parents are single-dose veil tail is unsatisfactory because this produces 25% normal, 50% single-dose veil tail, and 25% double-dose veil tail. You need to sort three kinds of fish and also the double-dose veil tails are slow-growing and not as attractive as the single-dose veil tails. It is better to obtain veil tails from a cross of a single-dose veil tail x normal, which will produce 50% single-dose veil tail and 50% normal offspring. Well, in our experience the same can be said for Longfin in bristlenose.
If you have bothered to read this far, and if you are anything like me, you are probably thinking, "Guess what Dave, this isn't an angelfish. It's an ancistrus. It's a different species. It probably has a different number of chromosomes. The genes may work differently". I can only say that every cross that we have done breeding longfin and standard fin bristlenose (in the hundreds) has shown us that it does work the same as it does with angelfish. If your bristlenose carries the gene for longfin, you will see it!
Comments are welcome as always.