A case of crossbreeding in Hypancistrus (L136 x L066)

by Yann Fulliquet

his is a little summary of what was observed during an accidental case of crossbreeding which involved two undescribed species of the genus Hypancistrus. I was keeping 5 Hypancistrus sp. L066 along with 4 Hypancistrus sp. L136. Both males and females were present for both species. Several caves were placed in the tank hoping to successfully breed both.

I actually never thought of any possible crossbreeding between the two, because their colour patterns are very different. With L066, the overall colouration is white with a lot of curved black lines. With L136, the overall colouration is black with small white to yellowish spots all over the body. In both species the belly is white. Their adult size is also different. L066 can grow to 15cm; they usually become mature at around 10cm. L136 grows to 10cm, and usually becomes mature at around 6-7cm. Everything went on pretty well. I noticed one day that one L066 male was in a cave. With this species, when a male is guarding a cave, it is usually a sign of his willingness to spawn, the rest of the time they will not use them. I did several water changes to simulate a rainy season and also to stimulate the pairs.

After a few days of treatment, I found a female L136 trapped with a male L066. I first thought that due to their differences nothing would happen. A day or two later the female was out. I checked the cave and I saw about 20 eggs of about 3mm in diameter. Even if I disturbed the male, he never ate the eggs and was taking good care of the eggs.

I believe this happened because of several reasons. The first one is that the dominant male in the tank was clearly this L066 male. He had the darkest colouration; his whole body was covered with odontodes. The other L 066 males were rather lighter in colouration and almost no odontodes were present, at least on the plates. At that time the females were probably not fully mature. My L136 males were also being dominated by the L066. I never found any of them in a cave. One of the L136 female was clearly ready to spawn and chose the only male which was "available" or ready to spawn.

After about 8 days the eggs hatched. I left the eggs with the male for about a week and then managed to take them out of the cave, rearing them separately. At this time they could easily be mistaken for young Hypancistrus zebra. They were placed in a separate floating plastic nursery. Just before they had completely absorbed their yolk sac, the young started dying en masse. I checked the water parameters, but everything was fine. I still only managed to save one young. I don't know if these are more fragile than others, but compared to L028 and L260, two other undescribed species of Hypancistrus, the young were looking as hardy as the others. This remains a mystery to me. Anyway, the remaining fish finally absorbed the yolk sac, and was fed with Spirulina tablet fragments, chopped bloodworms, and small pellets for fry. With this food, he grew pretty well: at about the same rate as other Hypancistrus species. At this time it was looking rather like miniature copy of the father. Still one or two spot like shapes could be seen. As time passed and as he was growing, I could see that the overall colouration was more black than white, the lines were disappearing to let spots take their place. Only the fins have the typical pattern of L066 with white and black lines. Most of the white lines on the body have totally disappeared. There are many white spots and several lines that look like spots, but are in fact interrupted lines.

Click on thumbnail images below for a larger image and mini factsheet.

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Hypancistrus sp. (L066) Adult male

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Hypancistrus sp. (L066) Adult male

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Hypancistrus
sp. "Hybrid" (L136 x L066)

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Hypancistrus
sp. "Hybrid" (L136 x L066)

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Hypancistrus
sp. "Hybrid" (L136 x L066)

 

At first I regretted that crossbreeding happened, as I like to keep pure strains of fish, but now I must admit it was an interesting experience. The fruit of this unusual spawn is curiosity. It is also a good thing to have such fish referenced, as with the increasing popularity of these fish, people could tend to create new and rare species. I sincerely discourage people to intentionally cross species, and if it happened by accident, the young should at no point be sold to someone else. There are enough species in the wild to please anyone and it is not necessary to create any new ones. Several people have told me that I should have kept more youngsters, so I could have tried to make them spawn with their parents. This would have helped to determine how closely related the two species are. But like I said, I am not fond of crossbreeding, and I do my best to avoid such things happening.

Originally published in CatChat 4(4): 9-10.
www.catfishstudygroup.org

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