Guppies dying

[artzechic]

I had 4 guppies. 2 female, 2 male. The water tested great, never has it tested any less than perfect since I set it up about a month ago. One of the males died about a week and a half ago. I thought that he might have gotten tangled in the yarn ball I'd put in for baby fry, so I took it out. But, yesterday, I saw one of my female guppies laying dead on the bottom of the tank. She didn't have any fungus or growths or anything, and the day before she passed the only thing I noticed was that she was swimming REALLY slowly and she was REALLY pregnant. So, I'm not sure if the incidents were related, or if it was just a sad coincidence and she died from pregnancy complications. Any ideas? my other female did manage to pop out a baby and she is about 2 weeks old now, in a different tank with my red cherry shrimp and doing great. I don't want to lose my other guppies, especially my last male because he is gorgeous, but I don't know what else to do since I see no visible illness signs, no odd fungus in tank, in gravel, etc, and I do 10% water changes every 2 days or so. Please help! :c

 

[TwiinKey]

What's your water temperature?

 

[artzechic]

water temp is 75 degrees at nite, and 78-79 degrees during the day

 

[TwiinKey]

Did they seem disoriented before they died? Like not swimming correctly (sideways or upside down) or not swimming at all?

 

[artzechic]

Nope. She was fine except for swimming slowly. I assumed cuz she was goober preggy. Everyone else was awesome. I have noticed my male is constantly chasing the females. He hardly ever isn't. But they don't act sick. Been swimming around faster than normal actually.