XFins

As I've mentioned elsewhere, X. birchmanni are majestic fish. They have brightly colored, splendid dorsal fins and "powerful" bodies. They are quite aggressive, yet mature males can generally co-exist without difficulty. These are all desirable traits that potentially could be transferred to swordtails and platies.

Defending their turf?

Five first generation tank-raised X. birchmanni males.

Lowfin X. birchmanni-domesticated swordtail hybrids are often large and colorful. Hybrid males have swords, but they are relatively short. These fish are moderately aggressive and frequently become the most dominant fish in a tank containing domesticated swordtails and platies.

Yellow Pigmentation

X. birchmanni contain gene(s) that specify yellow pigmentation. In wild X. birchmanni, bright yellow pigmentation is confined primarily to the dorsal fin and to a lesser extent to the caudal fin. Hybrids frequently contain yellow dorsal fins, but in some cases the body is also yellow. The F1 hybrids shown below have yellow body pigmentation.

Lyretail Hybrids

X. birchmanni hybrid lyretails are very nice looking fish. Unlike lowfin X. birchmanni-swordtail hybrid males, hybrid lyretails have relatively long caudal fins. In fact, it is often difficult to distinguish domesticated lyretails from these hybrids. The X. birchmanni hybrid lyretails shown below have well-proportioned bodies, nice dorsal fins, but lack the bright coloration of many available domesticated lyretail strains.

X. birchmanni-domesticated swordtail hybrids can often have very large bodies. The upper fish is a full grown (old) X. birchmanni male. The lower fish is a much larger F1 hybrid. This is often referred to as "hybrid vigor" when the hybrids are "better" than either of the parents in terms of a specific trait.

F2 Hifin Hybrids

I have been interested in producing a line of hybrid hifins that more closely resemble wild X. birchmanni. The F2 fish on the right are hybrids produced by crossing a F1 X. birchmanni-swordtail hifin back to a X. birchmanni female. These fish are relatively small, but exhibit some of the pigmentation (e.g. black spots on the dorsal) characteristic of the wild fish.

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Birchmanni Hybrids

Hifin Hybrids

X. birchmanni hifins have been described in the Interspecies Hybrids section. The hybrid shown on the left below, is a second generation hybrid (F2) resulting from a cross of a F1 hifin hybrid male back to a swordtail female. The hybrid on the right is a F1 hifin hybrid with the same irridescent blue-black body coloration and pale yellow dorsal fin that I have seen previously (see Gallery page).