My Molly Died

Water Parameters were fine. My 20 gallon is understocked so there was no quarreling. Everything was fine and I went to bed and woke up and fed my fish. My black male molly was doing just fine. I didn't look for about 4 hours and I came back and he was dead. It was not just floating around dead. His eyes were white, his fins were erect, and his scales were turning a weird gray. It was totally random and I don't know how he could have looked so dead so fast.

Forgot to take a picture before I removed him. Has anyone had this? Is it normal? Was something wrong with him?

 

Can you post your exact water parameters - pH, temp, ammonia, nitrite, nitrate? How long have you had him and what other fish do you have?

 

PH is 7, Temp is 78, Ammonia is 0, Nitrite is 0, Nitrate is 5. I have a twenty gallon planted tank with my black molly that died, a dalmation molly, a dwarf gourami, two platy, two corydora cats, and an apple mystery snail.
I've had him for about three months. He was in a 5 gallon when I first got him and now he's been in a twenty for about a month. He has been acting totally normal until he died.

Can you post your exact water parameters - pH, temp, ammonia, nitrite, nitrate? How long have you had him and what other fish do you have?

PH is 7, Temp is 78, Ammonia is 0, Nitrite is 0, Nitrate is 5. I have a twenty gallon planted tank with my black molly that died, a dalmation molly, a dwarf gourami, two platy, two corydora cats, and an apple mystery snail.
I've had him for about three months. He was in a 5 gallon when I first got him and now he's been in a twenty for about a month. He has been acting totally normal until he died.

I also want to mention I have a twenty gallon filter and a 5 gallon filter running. They are both cycled. I have pothos in the filter growing as well.

 

You noticed no aggression from the other molly or DG? And is this a 20 gallon long or high?

 

You noticed no aggression from the other molly or DG? And is this a 20 gallon long or high?

My tank is a 20 high. My deceased male black molly and female dalmatian molly used to be a bit territorial and chase each other when I dropped an algae wafer, but I learned that if I break the wafer up they each have their own and leave each other alone. Ever since then I have seen absolutely no aggression at all in the tank. The DG is very docile and doesn't pay attention to the fish and the tank is by me and I see the activity a lot through the day

 

Well, we can't watch our tanks 24/7 so who knows what occurred when your back was turned. Sorry, I know it's not a good feeling to not know why these things happen.