iv got 2 female guppys in my tank that sit on the bottom of the breeding trap. 1 is about to give birth and the other has just given birth. all the other guppys swimming about are fine could it be a desiese
Being prego is exahausting... perhaps that is all that you are seeing. Also, being in the breeder is stressful for some, they might be just a little scared.
Since you said they were in a breeding trap I would probably think that the guppy died because of the breeding trap. Traps are amazingly stressful for the fish and that can lead to death from either the stress itself or from diseases caused by the lowering of the immune system from stress.
I agree with the monkey. Maybe you should let your fish give birth in the main tank and then move the fry somewhere else if you can find any. Usually at least 5 live and don't get eaten.