Noticeable defect in giant in-breeding?

If you pay close attention, you may notice that some giants have irregularities in their finnage, particularly caudal. Check your auction sites and pictures of giants they're trying to sell you. For instance, some of its rays are fused together or not having a proper branching, middle of the caudal rays being folded heavily, etc.

We speculated that this is due to deep in-breeding that they're doing to produce giant genes. As the number of available giants decreases, due to lack of availability, the breeders do not have options but to choose whatever stock they have available, hence very limited available genes produced.

This is where you have an upper hand ;) As buyer, you can select good pairing where you can choose a female from one breeder and cross it with a male from another breeder. Of course the outcome may a little bit uncertain, majority would be "normal" bettas or half-giant, but you can start your own line this way, having better advantage compared to the initial breeders. This assumes that the initial breeders hate each other's gut, and they don't share their stock. Note that some breeders form their own club and actively share their genetic pool, but they usually don't particularly have "valuable" stock that you want to have (otherwise they would have produced and sold it long time ago since they have the man-power to do it).

It always strike us odd when we asked the breeders whether they have "another" similar fish to the one that they're selling and they responded back saying "no". This could only mean 2 things: 1) the one they're trying to sell is a one-off, very much instable, and has lots of disappointing siblings, or 2) they are being honest and really don't have any other similar fish in the spawn (gosh, what's the chance of that?!). Trying to get more information from them, sometimes, is very difficult. They are very reluctant on sharing this info as it doesn't really help them selling the fish ;)

So, before you spend your money to get that beautiful giant, perhaps you should ask a bit about the history and background of what you're going to get. Picture tells 1000 words, but also hide another 1000. If they try hard to avoid answering your questions, you know where you stand ;)