Mysterious cory death

[fballguy]

One of my cories had been acting strangly the last few days. He would be fine one minute then upside down the next. This morning I found him dead. All the other fish appear normal and parameters are normal. Was this just a freak thing or sould I be worried about my other fish possibly having the same thing. Any help is appreciated.

 

[greendeltatke]

How long have you had him?

 

[fballguy]

Almost 5 months now.

 

[DaisyTattoo]

If your water tests good then I wouldnt worry. You could always do a water change just to be on the safeside.

 

[CoreyK]

Several of my dwarf cories have ended up dead in the past week or two. Same as you, parameters are great, as are the other fish.
Strange?

 

[mvigor]

The same thing happened to me too. I lost 3 in my son's tank that had been in there about 10 months. I believe that my every other day feeding schedule slowly, slowly starved them. Believe me I feel terrible about it. I feed them every day now and have to do water changes a lot more often, but so far no more losses.

 

[TKOS]

I doubt every other day feeding would starve them. They would look very skinny and you would notice. Cories do seem to be intolerant of higher nitrate levels and higher salt level over a prolonged period of time.

With trouble staying upright perhaps there was a swim bladder issue.

 

[mvigor]

Now you've got me wondering. I had my routine down... 6 pygmy cories in a 10 gallon tank, planted. 25% WC every week was what was needed and done. I stopped doing test strips because it was always fine.

6 weeks or so before the deaths I had to trim the plant and I trimmed it back hard. I bet that plant had been soaking up a lot of nitrate and was part of the biofilter.

 

[TKOS]

Well a short spike in nitrates shouldn't be too much of a problem. Longer exposure will probably strat to affect fish like cories beofre other tougher fish.