Zebra Danio

[welshgirljo]

I've had 5 zebra danio's in my tank for the last 9 days. All have been doing well until this morning. I got up to find one of them looking very sluggish at the bottom. It is hard to tell whether he had has mouth open constantly or whether he had lost part of his nose. At times he moves up, swims around as normal for about 5 minutes then back to the bottom. He's now hiding amongst some low grass type stuff. I think his time is nearly up. Any idea what is causing it? All others seem fine, readings are fine etc. I have done a 25% water change this morning to see if this would help.

Looks like he has finally died. Hopefully the others will be fine

 

[WILDER]

Water stats would be good to look at, the mouth did it look fluffy, white patches around it, or rotting away look.