Well I've had my little group of six guppies for a while now, but recently decided to move them over to my 20 gallon after the arrival of my Cichlids. They practically have the tank to themselves save for a little cory, mini pleco, and one old Tetra whom doesn't seem to want to kick the bucket(even though its other group mates have been eaten/died...)
Anyway one of my females has suddenly started acting a little odd. Shes constantly sitting on the bottom of the tank, alive but unmotivated to move even when the others swim around her. Curious about it, I netted her and stuck her in the breeder to get a better look at her. Outwardly she showed no signs of injury or sickness and seemed to want to leave the breeder, so I let her go.....and back to the bottom. Pregnancy and getting ready to give birth are options I had considered, but I don't see how seeing as she has shown not a single physical sign of being pregnant. Her belly hasn't gotten any larger since the day I got her and there is no dark coloring to her stomach.
My heater also broke yesterday and the temp in the tank has been fluctuating a bit, but everyone else seems perfectly fine. Also did about a 35% water change yesterday, but I don't see how that could affect this lone guppy negatively.
Any suggestions as to what might be wrong? I'm very confused. I can provide pics of her too, if need be...