Undeveloped Fry Problems?

[guppyrookie]

Some of my guppy fries have undeveloped fins & tail. Their siblings have developed ones for their size. Has anyone had this issue before?

 

[PrairieSunflower]

Some of my guppy fries have undeveloped fins & tail. Their siblings have developed ones for their size. Has anyone had this issue before?

Could they perhaps be clamped rather than underdeveloped?

I've not had them underdeveloped before, but some (for fins) have been so transparent I couldn't see them, could always see tails though.

 

[zain611]

Could there be inbreeding?

 

[guppyrookie]

Probably not since the mother was already pregnant when I bought her.