Sudden Goldfish Death

[missmeliss]

So I had 4 Waken Goldfish in a 45 Gallon tank - They are all 4-5" in size and will be transferred to a pond when they outgrow the tank. I went away for a night and came home this morning to find one of them floating upside down with a black distended abdomen and it's mouth apparently "stuck" open. He(She?) was fine before I went away. I immediately tested the water with an API Master Kit and ended up with:

Ammonia: between 0-.25ppm
pH: between 6.2
Nitrites: 0ppm
Nitrates: about 7ppm

I have no idea what could have happened, the other 3 seem perfectly fine, begging for food and all.

Thanks in advance!

 

[WailuaBoy]

Goldfish suffer from numerous genetic digestive disorders, being that only one fish is affected; I wouldn't worry. Be sure to feed vegetable matter, like peas at least once a week to ensure proper health for the rest. I'm assuming the ammonia in your tank is a false positive reading. Good luck with the rest of your fish.

 

[missmeliss]

*drops Peas in tank* Thank you!

 

[jimv8673]

Sometimes fish just die for no apparent reason