Giant Redtail Blue Variatus

Photo: Pair of Giant Redtail Blue Variatus and male regular Redtail Blue Variatus

Xiphophorus species, which include swordtails, maculatus platies, and variatus platies, hybridize readily. A while back I wrote, when I was writing for Tropical Fish Hobbyist magazine, an article about some hybrids I had been working with. This blog provides an update on one line of hybrids I’ve been working on, the Giant Redtail Blue Variatus. After this blog, I will be doing a series of blogs concerning our various variatus strains that we’ve just recently processed and set up for breeding.

Long ago, way back in May 2012, Ron Finlayson, a fellow ALA member, gave me some of his very nice Blue Parrot Variatus. This fish is very similar to one of our platy strains we call Redtail Blue Variatus. I mated some of his female fish with our male Blushing Swordtails, a green swordtail strain with a red dorsal and back. As I typically do when there are sufficient genetic markers making it easy to identify hybrids, I didn’t bother using virgin females. Why would you use virgin females? You do so because females in the family Poeciliidae, which includes guppies, mollies, swordtails, platies, and most of the common livebearers in the hobby, have the ability to store sperm. As a result, if the male parentage of a batch of fry must be definitely known, the general practice is to raise virgin females. But, since these females are determined not to remain virgin, it’s necessary to almost daily inspect your fish and remove any developing males. Unfortunately, one precocious male can impregnate dozens of once virgins. Alternatively, you could isolate individual fry in their own tanks. Neither of these options is very workable in our operations. In the case of this cross, raising virgins wasn’t necessary because I’ve learned to recognize variatus/swordtail hybrids using a number of characteristics, including shape, fins, and color pattern.

As expected the first generation of hybrids were larger than variatus, much chunkier than swords, reddish in color, and they had very short swords. I set up the best F1s (first generation hybrids) for breeding. The F2s, the second generation of hybrids, were very interesting. Most were heavy-bodied and sported various shades of red. The males had swords of various lengths, ranging almost none to those almost as long as their Blushing Swordtail grandfather. Other fish were more interesting. One group, a single male and 14 females, looked like Redtail Blue Variatus, but were much larger. The photo at the beginning of this blog shows a standard male Redtail Blue Variatus, a male Giant Redtail Blue Variatus, and, in the background, a female Giant Redtail Blue Variatus. The male Redtail Blue Variatus is NOT a small specimen for his type. In fact he’s about two inches long (~5 cm.). The giants were LARGE!

The lone male and his harem were set up for breeding.

When we recently processed his vat, we found he still lived. Also three of his sons had grown to be equally large. We set up him, his three sons, and ten of his largest daughters for breeding. We also added a very large female variatus/swordtail hybrid from another cross to the breeding colony. She most resembles a very large Redtail Black Variatus. From her mating with the Giant Blue Variatus males we should get some other variatus color patterns.

This is what I love about fishkeeping; the development and improvement of fish!

Good fishkeeping!