1 Week Pregnant Guppy Guppy Dead

This morning everything was fine as I was feeding my fish before I went to brush my teeth but when I got back I saw something silver on the bottom of my tank on closer inspection it was a female guppy that I bought the other week was dead and I didn't know why she died because the tank is fully cycled 0 ppm ammonia 0 Nitrite 0 ppm Nitrate 5 ppm but what I noticed is the her bottom side was red and swelled and it looked like she had an infection of some sort

what you are seeing is her breeding tube. This is where the fry are released from. It's possible she wasn't able to birth a particularily large fry and it was that that killed her. Perhaps she was stressed. I've seen fish die whilst giving birth before - it happens in animals the same as it can happen with humans. Just one of those things. I'm sorry for your loss 

Unfortunately I just had a second female die from birth today just got home to see her body floating in the tank dead

oh I'm sorry to hear that. 
 
One death is bad but two ... Time to check the tank stats just to be sure nothing is going on that you don't know about. Check mostly for Ammonia and Nitrite but it's worth running pH and Nitrate tests too. Nitrates could be high and that could be a factor. Do you have a liquid drop test kit? These are the best for accuracy. I can recommend the API masterkit. I used it myself for years before trying out a JBL one currently. I'll be going back to API once this kit is done!!

I use a api mastekit my self and the readings are


Ammonia 0 ppm Nitrate 0-5 ppm Nitrite 0 ppm PH 7.6

Tank temperature is 78F

hmm that all looks fine. It sounds like you've just been very unlucky