Poecilia non grata

Question
I just took a good look at Pat (the female guppy that is being totally ignored by the males) and realized that she has a deformed spine. Looking at her from above, she has a definate C shape. Could this be the reason the males aren't interested in her?  

Answer
Hmm...
Deformed spines can be genetics. But they can also be highly caused by vitamin C defienciencies. Insuring fish get a complete and balanced diet with plenty of vitamins should prevent this from ever happening. Fish in stores can develop this from improper care before going to home aquarists, or something may have happened in the hatchery before the fish ever got the store.

Your fish may have a genetic problem. I have seen this a lot with guppies and really can't pinpoint the problem being the diet so I have to blame it on genetics. It's best not to breed curved spine guppies to avoid passing on her genetics to the babies. I prefer humane methods than the aquarists usual methods of dealing with curved spine fish with culling and destroying them. I however, believe even the not so "perfect" look in our mind fish have a right to live.....SOOOO. I keep my few curvy guppies in a aquarium of their own with companions.
I might imagine your males could be ignoring Pat because of her oddness but I haven't seen a male yet turn down ANY female. It's a wonder why they haven't been interested in Pat.

I hope this helps! Best wishes!!!
Happy fishkeeping!
Karen~