I got the idea for this project because of 3 main reasons. 1) I wanted to keep a line of top view fish, and did not want to do what everyone else was doing (Ranchu). 2) I wanted to create a fish that as far as I knew no one else in world possessed. And 3) I wanted the genetics to be simple enough that it would not be a nightmare to try and create what I wanted. Albino acts like a simple dominate/recessive in goldfish, just like people. (aa) is albino and (Aa) (AA) is normal pigment.
Finding albino goldfish is relatively easy, although which breed to start with needed to be chosen carefully. I chose the albino “telescope” picture below (Figure 1).
Figure 1. Original albino “telescope” fish.
Even though it was labeled as a telescope, its eyes were so small that is was basically considered a fantail. Which was great, because I would not have to do much to get the telescope gene out of the population (if it was even there?). It was a twin-tail already, so I would not have to worry about that trait, since the bubble eye was also a twin tail. The orange color albino was not what I wanted, I preferred a white albino, but I had no choice because this is all I could get. I knew introducing the dorsal fin gene(s) was going to really mess with my bubble eyes backs, but again I had no choice with which albino I was starting with. As you can expect the F1 generation offspring was a mix of the 2 parents’ traits (Figure 1 and 2). None of the F1s were completely missing their dorsal fins, which I expected. And all the bubbles were reduced on these fish to toadhead proportions. I had no problem with either of these outcomes, because I knew that successive back breeding to the bubble eyes would slowly eliminate these traits.
Figure 2. F1 cross (Aa) of original albino fish and a bubble eye.
Figure 3. F1 cross (Aa) of original albino and a bubble eye.
The next step was to breed the F1 brothers and sisters together, and since they both carried the albino gene (Aa) somewhere around 25% of their babies would come out with the albino trait. I was not too concerned with inbreeding at this point, because I knew in the next generation I was going to outbreed these fish to two separate unrelated bubble eyes. After crossing the normal colored F1s, I got the F2 generation babies. Culling the F2s for albinos was easy because I threw away all the dark fry, because they were obviously not albinos. I kept all the F2 albino fry and grew them up. The quality of these F2 albino bubble eyes was really poor, as could be expected (they still contained 50% fantail genes). The backs were not smooth, with occasional spikes, but the bubbles had enlarged a bit beyond the F1 generation. Unfortunately, I do not have any pictures of these post-F1 generations.
Now the process of out breeding could begin. These F2 generation fish were albinos (aa), but were still 50% fantail genetically, but I crossed them to two separate pure bubble eyes. This is a really important step to reduce inbreeding, assuming you have access to more than one fish for the outcross. Always when you have to inbreed to get the desired trait back (albino) you can make the fish half siblings, which reduces inbreeding greatly. These F2 albinos were (aa) and I crossed them to two different normal colored bubble eyes (AA), and all the F3 babes came out normal color, but they all carried the albino gene (Aa). The most important thing though was the fantail genetics was cut to 25% with the outcross. The other important thing was that by crossing the F2 albinos to separate pure bubble eyes I would not have to breed full siblings together again, like I had to do in the F1 generation. These would be half siblings that were backcrossed in the F3 generation. Crossing the F3 normal colored half-sibling bubble eyes gave me albinos in the F4. These F4 albinos were then outbred to two separate pure bubble eye goldfish again (different line than any used before), and the percentage of the original fantail parent was now down to 12.5% in the F5 generation. This process was then repeated again for the F6 and F7 generation, which means that these fish were only 6.25% of the original albino fantail (Figure 9). At this point there was no trace of the original albino fantail parent’s traits left in the bubble eyes, (Figure 4). In the future I plan on continuing to outcross the albino bubble eyes to normal bubble eyes to introduce more genetic diversity into the line, as I am achieving phenotypically what I wanted (Figure 7 is not a bad fish!). The only thing I am displeased with is the tails of these fish, it is too long. So I have another pure bubble eye (Figure 6) that I will be using to tighten up the tail.
This would be a good time to introduce the idea of a “foundation” fish. The black bubble eye pictured below (Figure 6) is not only an outstanding looking fish in its own right, but it is an outstanding breeder. I am calling it an outstanding breeder because it is better able to pass on its desirable traits, nice split and shaped tail, beautiful uniform scales, and smooth back, to its offspring EVEN if bred to poorer quality fish. This black female bubble eye pictured below is a DandyOrandas.com fish. However, the orange bubble eye pictured below (Figure 5) is also an eye catching fish in some respects, however it is a horrible breeder. All of its offspring had fused tails or single tails and their backs were inconsistent. The only redeeming quality to this fish seems to be its large bubbles. This was a fish I bought at a local shop and is not suitable for breeding. Therefore, I will work on concentrating the genetics of the black fish into my bubble eye line. This is the definition of a foundation fish, a fish that is of such outstanding quality and breeding potential that you use it as the basis for your line. Not only do you try to begin your line with the foundation fish (which I wasn’t able to do), but you reintroduce its genetics through inbreeding to improve the line and concentrate the characteristics that are desired. This is not to say that you do not have other genetics in your line, but you want to maximize the genetics of the outstanding quality fish, while using the built in genetic diversity from past fish to avoid the negatives of inbreeding. This is where the art comes in to breeding, and it is not as easy as it might seem.
So in summary, the main lessons of this article are understanding outcrossing and inbreeding. These techniques are not as important in goldfish, as in species like large mammals, given that goldfish can have 1000s of offspring at a time. In animals like rhinoceroses that have only a single offspring, and only a baby every 3-5 years, having 50% of your offspring with genetic issues can be devastating. But in goldfish that have 1000s an offspring at a time, if you have to throw away 50% of your babies because of genetic issues it is no big deal really, because you were going to cull that many anyway, and you are still left with 100s of offspring to select from. The albino gene is easy to work with because it always shows itself when in recessive form (aa). And it is controlled by a single gene (most likely). Therefore, anytime you breed an albino fish to any normal fish, you know any resultant offspring will at least carry the recessive gene (Aa). Inbreeding brother to sister will then always give you the recessive trait back again. Then those albino fish are outbred to a pure unrelated bubble eye not only to “cure” the inbreeding you just implemented, but outcrossing to the pure bubble eye also restores more of the bubble eye phenotype every other generation. Once you get to about the F10 generation there will be basically nothing left in the future generations of that original albino “fantail” parent.
Figure 4. F8 albino bubble eye goldfish (aa).
Figure 5. Pet store origin bubble eye goldfish (AA).
Figure 6. Black bubble eye goldfish from Dandyorandas.com (AA).
Figure 7. F6 albino bubble eye goldfish (aa).
Figure 8. Representation of breeding scheme to create albino bubble eye goldfish. Each albino fish regardless of generation is only shown crossed to a single outcross. However, multiple fish were used. Also, the outcross fish in each generation is pictured as the same fish, but that was not the case.