Random Guppy Death?

[007 Snail]

I'm relatively new to having fish. Last weekend, I purchased 4 zebra danios and 3 guppies for the tank I currently have (yes, it was cycling before). They get along relatively well and nobody has any shredded fins, so it's all good. But this morning, I found one of the guppies dead.

She was doing well yesterday. Active, healthy-looking, and definitely eating. I don't see a reason for her to randomly die. All of the other fish are fine and look fine. There were no wounds on her and her fins were perfectly fine. She's been eating with the rest of the fish.

What could have killed my fish?

 

[FLFishFanatic]

Welcome to AA!

You may want to check your water parameters. If you don't have a test kit, many stores will test it for you.

 

[DragonFish71]

Welcome to AA

+1

Adding that many fish at one time could have overloaded your tanks good bacteria.
It is recommended to add fish slowly, a few at a time. This way the bacteria have a chance to build up to convert the waste. Add too many at once and the bacteria don't have a chance to reproduce to do their job.


Another thing could be just bad stock. The guppy could have been weak from the beginning. But I'd go with too much stock at once first.