Fish Keep Disappearing

[STEWARDSONS]

I have now lost 3 cardinals in 2 weeks.

I had 4 since the start and added 6 to them, a few days after putting ht 6 in I noticed they had white spot so I treated the tank and it went away.

The fist died and I fished it out and thought it was a one off. Well now 2 more have completely disappeared, one last week and one in the last 2 days, there is no trace of them anywhere.

Is anything eating them and why are they dying? The water reads ammonia 0, nitrite 0 and nitrates 40.

The ammonia was up to 0.25 about a week and a half ago ago but I did a water change and its now better.

All the other fish are ok.

 

[Tizer]

I forget your stock list so cant really comment.

Cardinals can easily die at night and be gone in the morning, yummy food for other fish, without doubt

I had a few disappear on me when the tank as new, no idea what happened, some fish die and sink, some die and float.

 

[STEWARDSONS]

in my tank i have,

cardinals
scissor tails
rams
emperor tetra
popendetta furcata
plecs
ADF
denisonii barb