Photo: A possible Poecilia reticulata (guppy) x Poecilia mexicana, Campeche (molly) hybrid in front of a grid to show size.
We found the fish in the above photograph January 15th of this year. Before I describe the fish and argue why I think it might be a hybrid, let me give you some background.
We breed most of our mouth-brooding cichlids in 300-gallon vats (see photo below), placing two to three males and up to 50 females in each vat. Each vat is equipped with devices we call cichlid hotels and fry cages. The cichlid hotels are made with 2” PVC cut to 12 inches in length with six cylinders of aquaculture netting tie-wrapped around them (see second photo). These provide shelter for the females when they tire of the amorous intentions of the males. We usually place five hotels on one side of the vat. We also place two or three fry cages in each vat. Fry cages made with 1/4” or 1/2” aquaculture netting forming an open topped cylinder about 30” in diameter. The same netting forms a bottom (see third photo) and four PVC legs keep the cylinder off the bottom of the vat. We place two cichlid hotels in each cage. These assemblies provide shelter for fry when the females release them.
A 300 gallon vat set up (minus the water) for cichlid breeding with three fry cages and various cichlid hotels.
A cichlid hotel used to provide cover for females, subordinates, and juveniles.
A fry cage used to provide cover for cichlid fry and juveniles.
A fry cage is placed in a breeding vat to provide a refuge for fry and juvenile fish.The breeders are placed in the 300-gallon vats equipped with the cichlid hotels and fry cages. We typically also stock the vats with feeder guppies (Poecilia reticulata) to provide forage for the fish and to inure them to the presence of small fish. Guppies, surprisingly, even in vats with predatory cichlids, reproduce well. We produce them in cichlid breeding vats and offer them to our wholesale customers as feeder fish. In some vats we also place mollies, both commercial aquarium strains and species such as Poecilia mexicana, P. latipinna, P. petenensis, and P. velifera. We are able to produce significant numbers of mollies this way. The breeders remain in the vats for three to four months, depending on the time of the year, before we harvest the vats. At harvest, we net out the fish, inventory the breeders, harvest the juveniles, and return the breeders to the vat for another breeding cycle. If there are guppies or mollies present, we restock breeders and harvest the surplus for sale.
On this particular January day, we harvested our Iodotropheus sprengerae (Rusty Cichlid) vat. In my never ending quest to increase production in each vat (Susie, wife and business manager, insists on profits), I continue to test poly-culture. Poly-culture is the growing of two or more species in the same space. In this case, I had stocked the vat with I. sprengerae breeders, feeder guppies, and Poecilia mexicana, Campeche (Campeche being the collection location in Mexico). As we sorted the fish, guppies were placed in a bucket to be separated into breeders to be returned to the vat and sale fish to go into 55-gallon holding vats. While selecting guppy breeders, I noticed one large, red tailed fish, too large to be a guppy but clearly not a P. mexicana. I put her in a jar for closer viewing.
I say “her,” because the fish had the typical fan shaped anal and ventral fins of a female Poeciliidae (the family both guppies and mollies belong to). Below, in the order of possible hybrid, guppy, and P. mexicana, are photos of females for comparison purposes. Note the male P. mexicana below the female.
Upon examination, the possible hybrid combined traits of both P. reticulata and P. mexicana.
- Her caudal fin shape said guppy, but she sported an orange caudal color reminiscent of that of a male P. mexicana instead of the clear caudal fins of female feeder guppies.
- Her head was more guppy-like with the eye closer to the upper edge of the head while the eye is set lower in P. mexicana.
- Her body, while more elongated than that of guppies or P. mexicana females, showed the dip after the dorsal typical of P. mexicana.
- Unlike guppy females, she showed no gravid spot, the black patch in front of the anal fin. Guppy females have it from birth. One can see through the transparent scales the guppy version of a uterus. Female P. mexicana do not show a gravid spot since their scales are not transparent.
- Her body color was rosy from the dorsal and anal fin back to the caudal, a pattern not shown by female P. mexicana but is in the males.
- The distance between the ventral fins and the anal fin was, like that of P. mexicana, greater than that of a guppy.
- She was much larger than the typical female feeder guppy just like female P. mexicana.
A possible female guppy x Poecilia mexicana, Campeche hybrid.
A female Poecilia reticulata, common name guppy.
Poecilia mexicana, Campeche female.
Many people have produced guppy/molly hybrids; it’s apparently easy. But I’ve failed to produce guppy/molly hybrids despite trying many times (so-called experts can and do fail). The interesting thing is that the hybrids are invariably (from what I hear) male and sterile. So, if this fish is truly a hybrid, it’s a first hybrid for me and a rarity in being female.
While we have over 700 vats, I only have 11 aquaria set up (well, set up if you count them being on stands usually without water or fish in the office). I picked a 40-gallon tank in which to put the fish. For companionship I took a male guppy from the vat she came from. I added some hornwort (Ceratophyllum demersum) and some scuds. Scuds are a small shrimp-like crustacean we raise for sale as food. Ours are a Gammarus species or maybe even a different genus. There are more than 90 species of freshwater scuds in North America alone. We’ve not been able to get anyone to identify our scuds despite shipping them to many universities. She remained there until a week ago when I took her out to pose for the photos herein. So far, she’s produced no fry.
So, what do you think? Hybrid or just a strange guppy? Let me know your thoughts.