Guppy Tail Variation

[Atr0pos]

hi all, my 8 year old has a question about his guppies.

His pet store fancy guppies had babies. All of the original fish were solid red or yellow with regular fan tails. About half of the new batch (all of the males) have a distinctive v shaped notch in their otherwise normal tails. The notches are clean and do not look like the result of disease or injury. There is no membrane connecting the two halves of the tail, it's a solid gap.

I tried. To Help him figure out what's going on with the fish, but we are stumped.

 

[fish48]

it's genetic due to inbreeding also when two different species of guppy bred together sometimes not genetically compatible creating unusual tail and fin shapes apart from the v shape in the tail the fish should live a healthy life