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When to Outcross Betta Strains

When to Out-Cross Betta Strains and When Not To


The everyday attitude from so many on line and books from authors who know next to nothing that “breeders must out-cross”, is so prevalent that I almost have to discourage it 100% with most aquarists. However, with that being said I guess I should add there are times that it becomes absolutely necessary in order to save a betta line. Many of you don’t understand why one should out-cross vs. inbreed or even start over with a new line when it is at a point of a fail. Even proper out-crosses by seasoned breeders can sometimes cause many more years of work to get a line back to where you want it. You are reading that correct “years”. It is often simply much easier and much better to start over with a better line or your line bred back up’s (you did do a backup line right). The key is to a good breeding program with bettas is to learn what will be most productive way when trying to improve your line.


There are two main reasons I want to touch on with out-cross in bettas. One would be to boost the immune system on an older line and the other would be to introduce genes that do not exist in your current line of bettas and no other reason. Waiting for the right mutation to come along is painfully slow (maybe hundreds of years, or longer but not in my life time for sure). Therefore, you would find an unrelated betta that exhibits the desirable trait you need and breed it into your established line. It really doesn’t matter if it’s the same strain. In fact, sometimes it really helps if it isn’t the same. Simple, right? Well, not quite you need to hold on here. You need to think here because whenever you out-cross, you not only risk bringing in undesirable genes, but almost certainly will every single time you try it. Some of these may be recessive and may not exhibit the unwanted trait for a few generations or longer and then you line falls apart and random junk pops up like a bad cold in church. Even if you don’t bring in any undesirable traits, you will always have the loss of the expression of any desirable traits that are the result of recessive genes your line contained before the out-cross. Your super red will likely no longer be as red or you pattern on your nemo will be crap. The perfect body shape your line used to have, may not be so great and form will suffer. The pairs may not lay as many eggs, etc. You can get those traits back in your line, but it will require more generations of inbreeding to do so and some very selective breeding and years to correct.


So, whenever hear the dumb guy say you need to always out cross, you can usually plan on needing a minimum of a few generations of very very careful inbreeding to accumulate undesirable recessives so you can eliminate them in your bettas. In addition to that, you have to work on accumulating homozygous pairs from the spawns of all recessive genes that are desirable, so they will express the trait. Most of the time out-crosses can leave you with even more work than inbreeding and will most likely take much longer to see the results you want and producing junk all the way to the end. The more ornate your strain is, the more an out-cross will disrupt the expression of those traits every single time. In the hands of the wrong breeder or the breeder who listens to the dumb guy saying to always use unrelated pairs, an out-cross or too many out-crosses can degrade the look of betta far beyond recognition of any real standard. I guess this would be the point you could make your own standard like some breeders do when their idea of genetics does not fit the norm. The out-cross may many times introduce health and vigor, but it will likely be at a cost of degrading the bettas appearance of the current line.


The most important out-cross time would be only if your line has many problems. At this point you have to decide if it would simply be easier or more productive to start with a new line from a known breeder or strike out on your own again. The best decision might be to buy a known line and add to your line. However, there are times when you absolutely must keep your existing line going if you are the only one who has it. Usually this is when it contains a desirable trait that cannot be easily added to the line from another source. In this case, in order to preserve that trait, you must out-cross and accept it is going to be a long road to beautiful bettas again. Whenever I am confronted with a line that I must keep, but one that needs a lot of work, I almost always resort to an out-cross with wild fish even though the color layers are not the same as domestic stocks. Wild fish always have varying genetics, but nature has made them far stronger with more consistent positive traits than our man-made weaker betta lines. The chance of introducing unwanted recessives when using wild fish is very low if you know what you are doing. This is another good reason to use wild fish. Getting wild fish to breed with our domestics, is a challenge all its own and we can save it for another subject altogether.


After the out-cross, it can take three or more generations of inbreeding to accumulate all the desirable recessives of the betta line we are trying to preserve. In addition, when using wild fish, the time it takes to produce each generation is usually extended a little (it’s difficult to get wild fish to breed with your domestic at times and spawns can be small). I’ve had several projects like this take 9 years and longer like on super black or cellophane bigear, but even the first generation of the wild/domestic cross is usually a substantial and immediate improvement in many areas, like body shape, finnage, vigor and behavior. The results have always made the extra years well worth the time.




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