Okay, I had the guppy in a net, and she died last night. Woke up this morning, found another female guppy dead. I tested the water:
Ammonia-0
Nitrite-0
Nitrate-between 5 and 10
So, water parameter's seem to be okay. The guppy I found dead this morning, though, looked really weird when I took her out of the tank. For the past few weeks or so, she's been really fat, so I figured she was pregnant. When I took her out of the tank today, there was a big hole in her belly. It's sort of split in the middle, and hollow inside. A few days ago I also noticed something red and spiky sticking out of her a tiny bit, behind the fin on her underbelly, where poop typically exits the fish. I see this same thing on a female guppy still alive in my tank, except in front of that fin. Is it possibly an internal parasite??
Attached are pictures of the dead guppy when fat and alive (sorry it's kinda blurry), and the dead guppy with the hole in her stomach. Any information would be helpful, as I do not want any more fish dead!!