Mysterious Massive Fish Death!

[benny]

Hi guys,

Got up this morning and look into the 5 footer. All the Nannostomus beckfordi died all over the tank (about 50 pieces). No visible signs on the body. Some of them are in perfect condition, the rest were of course feasted on by the shrimps. Very strange.

None of the other fishes are affected, but only this particular species. Even the 3 line pencilfish were fine. Did a quick check on the water parameter and found nothing unsual.

kH at 1
pH at 6.2
NO3 at 10 ppm
NO2 at 0 ppm
NH3/NH4 at 0 ppm

No logical explanation, but really lousy feeling. Especially when it's first thing in the morning. Now my day is ruined.

Cheers,

[bclee]

What was the last thing you did on the tank?

BC

[checkerboard]

I recently experienced the same thing when almost my entire school of sundadanio axelroldi "disappeared" overnight! almost 30 of them. Unexplained. Other fishes are all fine! Strange, but they have already adapted for about a week or so, and were feeding well and growing when they suddenly died.

saw some dead bodies, but my tank is too dense to recover all of them.

[juggler]

Oh dear - they were so beautiful when I saw it last Saturday.
Did you add in any plant or fish lately?

[benny]

Didn't do anything to the tank. No new plants. No new fishes. No water changes yesterday, no fertilizers added either. Temperature controlled by chiller so stay at 25 to 27 degrees.

The fishes weren't new either, have been there for quite a while and now starting to look really good. Perhaps 30 Sep was the expiry date.

The microrasbora are now all over the place, looking really happy. Hmm....

Cheers,