midnight blue sailfin mollies

Midnight Blue Sailfin Molly

Photo shows a shoal of Midnight Blue Sailfin Mollies.

This molly, the Midnight Blue Sailfin Molly, is a relatively new creation of ours, but it has a long pedigree.

I’ll quote myself in an article published in Tropical Fish Hobbyist magazine.

“In October 2008 I set up a test cross of Poecilia petenensis, one of three wild sailfin molly species, with our gold wag lyretail sailfin mollies. At that time I was hoping to improve the lyretails in our mollies and thought P. petenensis might help since one of our strains of that species had a short “sword.” Ultimately, that proved to be a vain hope. Despite the lack of improvement in the F1s (first generation of hybrids), I persisted and raised large number of F2s and F3s. Even rearing large numbers of fish and persisting through three generations, the lyretails weren’t improved. Realizing my original purpose wasn’t going to be met, I almost discarded the line. But being persistent (read stubborn), I kept the line going and in the fifth generation some interesting fish serendipitously popped out. These fish were light gold with opalescent bellies. They weren’t very attractive, but they were interesting. That was enough for me to try one more generation. The opalescent fish were set up for breeding.

In another example of serendipity and also the result of raising hundreds of fish each generation, the F6 generation produced two males and two females with blue on almost white bodies with black patterning in the fins and on the body. This was an unexpected result. They were dubbed “blue freckle sailfin” mollies. Blue for the blue color and freckle for the black freckling. The four fish were given their own breeding vat.

That’s where we were in May 2013… Since that time we’ve gone through two additional generations. In the process, we’ve discovered the white body breeds true; it must be a recessive gene. Also we’ve discovered most of the offspring are blue freckles, but we also get fish that are just white with no freckles or blue color. It appears the blue color might be linked to freckling. The fish colors fall into four categories 1) white (very similar to silver mollies), 2) blue freckle, 3) much darker fish that Ashley, our hatchery technician responsible for livebearers, calls “midnight blue,” and 4) white fish with gold overtones. We purge the white fish. The fish with gold overtones have been segregated and we are working on a fish we call the “silver bronze” molly. The midnight blues only appeared in the last generation.”

That article brought us up to June 2014, about a year ago. Since that time we have continued working with this strain. Last week we processed this strain again. The photo shows two males and five females of our new breeding colony. The males are young and will grow larger dorsals. The strain doesn’t yet breed completely true; we still get some blue freckles and silvers. We hope to improve the blue color. I imagine a deep blue with the black filigree. It’s also interesting that the females especially show a wag pattern, black fins.

Once we’ve set the strain we’ll begin distributing this fish to the hobby, may be in the next couple of generations.

Good fishkeeping!