Guppie looking very ill!!

[galaga-girl]

I have had a VERY fat female guppy for a few weeks now, obviously she is pregnant. This morning when I got up she was on the bottom, her tail is missing and her belly has bright red spots on it.
Anyone know what is going on???

 

[Ems]

I'm not 100% sure on what it could be. The first thing I would check for is to make sure there are no signs of fin loss on any other fish, make sure there's no fin-rot or any other disease. I noticed the other day that my oldest male guppy's tail was looking very short, but soon discovered that the other males were the ones that munched it! I don't know what the red dots mean, maybe you should isolate her incase there is some sort of disease.

 

[galaga-girl]

None of the other fish are losing their fins and they all "seem" to be fine. She died about 20 mins after I posted the message. Her whole belly was bright red. I have no idea what it was, I hope no other fish get it!