They appear every now and then in various spanish populations. Adult specimens have been observed several times, as well as albinos, hypomelanistics, etc. Since it's a species that frequently inhabits heavily sedimented water masses with minimum or nill visibility and they will remain aquatic year-round if given the chance, these kinds of mutations (as long as they are not associated to others) don't seem to have much of a deleterious effect on their survival.
The origin of the captive population is...uncertain. Of course, as it couldn't be any other way you have people claiming to be the original producers of the only genetic line in existence, but in support of this all we get is the claim and nothing else. Nothing confirmed to a reasonable degree. Considering that they are not an isolated ocurrence in the wild, and how widespread they are today, it's not far fetched to assume independent illegal collections and therefore independent genetic lines, which at this point may have merged.
Regardless of their origin, their future seems more certain, and it's not good...Yet another species that falls prey to ridiculous standards of selection applied at any and all costs.
