mystery illness

[queeny]

Hi. Yesterday, I noticed that some of my black skirt tetras were gasping for breath, swimming near the surface and seemed to have a cottony growth on their heads. By the end of the day, one was swimming off kilter and tucked by the water filter. I thought it might have been a fungal infection (although having it on several fish seemed unusual) so I treated the tank with melafix and pimafix. Today, the tetras seemed more normal and the white on their heads was gone. By the evening, two were back to swimming off centre (even being moved about in the water current) and gasping for breath. I checked the ammonia, nitrates and nitrites and all were normal. The only thing different in the tank lately is that they laid eggs last week (it seems to be 2 females that are in the roughest shape) and 1 month ago I put in a carbon dioxide generator using the pop bottle, yeast and sugar method. I have done a 25% water change and removed the carbon filter from the fluval but I don't know what more to do with them.

Does anyone have any suggestions? :well:

[Qattarra]

How old is your nitrite test kit? It does sound like a nitrite spike. Do another water change, see if this helps a bit. Maybe do a head count or look for any dead fish that may be trapped under something. I hope all gets better and you don't lose anybody else . Sue

[Sam Chicklets]

Maybe you are putting to much co2 in the water and displacing the oxygen

[queeny]

How old is your nitrite test kit? It does sound like a nitrite spike. Do another water change, see if this helps a bit. Maybe do a head count or look for any dead fish that may be trapped under something. I hope all gets better and you don't lose anybody else . Sue

How old is your nitrite test kit? It does sound like a nitrite spike. Do another water change, see if this helps a bit. Maybe do a head count or look for any dead fish that may be trapped under something. I hope all gets better and you don't lose anybody else . Sue

The nitrite test kit is only a couple months old. Fortunately, in this tank, I only had the 7(now 6) fish total so everyone was accounted for. I hope things get better, too. Thank you.

Maybe you are putting to much co2 in the water and displacing the oxygen

I was worried about the oxygenation in the tank, too, so I had been removing the carbon dioxide generator in the evening. There was some redness around the gills so I think you might have something there. Do you know a way of regulating the oxygen in the tank?

[Sam Chicklets]

You could use a bubble counter and adjust the flow in accordance. What I would do in your situation though is discontinue use alltogether for a few days and see if your fish improve.

[werner]

Maybe you are putting to much co2 in the water and displacing the oxygen

It doesn't happen this way- CO2 and O2 concentrations aren't dependent on one another. Both high CO2 (even if O2 is fine), or low O2 (even if CO2 is fine) can cause gasping.

Make sure you've got enough water movement at the surface of the tank (from your filter or a powerhead), this will give CO2 a chance to escape and O2 to be absorbed. Also, higher temperatures will limit the amount of O2 in the water.

[Guppygirl]

Another thing that you could do would be to add an air stone to the tank, with an air pump. This inceases surface movement and helps the oxygen in the tank. I had a similar problem when my tank unexpectedly cycled (bacteria bloom) just this week. Woke up to find my fish gasping for air, quickly added the air stone and they have gotten better. Hope your fish recover and you find the problem.