The Asian Blau Gene

The Asian Blau Gene

Albino Blue Topaz

Albino Blue Topaz – Photo by Bruce Yates (Bayway). Used with permission.

When trying to create new varieties in your fishroom, it helps to know what genes are there and how they work. The Asian Blau gene is one of those that I have in my line of Albino Blue Topaz. Let’s take a look at this mutation.

I’ve stated before that it’s imortant to know your lines. The Albino Blue Topaz is, at it’s base, a HB Red. These can be X-linked, Y-linked, or both. The albino and Asian Blau gene have been incorporated into the genotype to produce a new variety. The Neon Blue, a HB Red with the AB gene mutation, was first produced in a Singapore fish farm. From there, the AB gene has been used to create other varieties such as the Albino Blue Topaz and Blue Grass.

Let’s look specifically at what this gene is and how it works. The Asian Blau gene is a modifier that acts differently in it heterozygous and homozygous states. First, the AB gene is dominant. In its heterozygous form, it removes the red pigment which allows the reflective blue pigment in the next layer of skin to show. In its homozygous form, the AB gene affects red and yellow color cells, allowing the black pigment in the skin to be seen through the reflective blue color layer. These fish have a gun-metal blue body color and somewhat smaller finnage. They also tend to be smaller and genetically weaker than their siblings. I tend to cull males, but females can be used for outcrosses to Red males to produce 100% Blues in the F1’s. This is a good way to introduce the Asian Blau gene to other Red lines. An interesting note about homozygous albino Asian Blaus. Since there is no black pigment in the albino fish, and the red and yellow color cells have been affected, the body is a transluscent white. Again, they are weaker and smaller, but still nice fish to work with.

You will never produce a true breeding line utilizing the Asian Blau gene. That’s because you won’t produce 80%+ identical males. Mating heterozygous AB fish will produce 25% Reds, 50% Blue Blaus, and 25% Asian Blaus (Luke Roebuck referred to these as an Asian blau cheat). Knowing how this mutation works will allow you to produce a line that is uniquiely your own. Don’t be afraid to experiment. If you’re not happy with your resulting fish, you can breed the gene out by using only your Red fish. Best of luck!



Owner at ASA Guppies
My name is Tony Anderson and I've been raising fish for nearly 40 years.  I've been seriously breeding Guppies for the last 15 years.   I am a member of the Greater Cincinnati Aquarium Society and the IFGA.

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