Big dorsal female moscow guppy

[John_S]

How soon can you see the BDS on a female moscow guppy. I purchased some BDS female guppies that are about 3-4 months old and the dorsal looks like a regular dorsal with no signs that it's bigger or longer. Was I just sold a regular females not a BDS?

 

[Colin_T]

Never heard of a big dorsalf fin guppy. However, most male guppies don't have full size fins until they are 6-12 months old. It might also be a male trait (male fish usually have longer fins than females), in which case it probably won't show up in females.