Originally Posted by dman
Is it safe to breed to sibling bettas together? I always wondered why diagrams or inbreeding examples are always, the offspring to the father or offspring to the mother.
Safe? Well no. It is never "safe" to breed siblings together. Why? because it amplifies the possibility of bad traits coming out. It also amplifies the good traits as well, so it makes breeding for a trait easier. Therefore you have a much better chance to breed for what you are looking for. It's why breeders often inbreed.
It was inbreeding in the early half moon lines that led many lines to fail due to sterility. There are many lines now to choose from thankfully...
Best of luck,