Dying spree

[Sven]

but aren´t bettas able to live in very low O2? I think I heard somewhere that they where a bit like labrynth fish in that sense? Might be wrong.

But I´m pretty sure I have not been battling gill flukes, I looked very closely at all the fish after they started dying, and I found no-one that was breathing rapidly. They seem to have died to quickly for gill flukes to make sense.

[TheOtherGeoff]

Sven - betta's are labrynth fish. they have no need for 02 in the water. they just need to be wet.

i had a problem like this before. lots of starnge and sudden deaths. going from one group of fish to another. i treated with melafix as an antibacterial and the dieing stopped. so there was some sort of a bacteri in the tank killing the fishes.

[LS6 Tommy]

Originally Posted by Sven

Yes, I noticed rapid breathing when they were close to dying. I had also been thinking that this might be gill flukes, but this happened so suddenly that it didn´t look like gill flukes. Did your fish in the end look like they were half paralized? then suddenly darting somewhere an lay there for some time again before darting of again? Mine sometimes just floated around like they were dead, but were breathing, then they tried to svim off but didn´t go far.
The first deaths I didn´t think co2 poisoning since I hadn´t seen any fish gasping for air at the surface.

Sounds like the last stages of Ich to me.
Ich is most dangerous when you can't see it. It gets into the host's gills almost immediately as it is only infectious when it is in it's "free swimming" larval stage. That is also the only time it can be treated, hence the long treatment period of most Ich cures. The spots on the body are when the "adult" Ich is ready to drop off as spores to reproduce. Just because you can't see it doesn't mean it isn't there.

Tommy

[Sven]

But if it were ich, wouldn´t the fish have died in a shorter time period? They have been going one at a time for about 2 months. And out of the 15 dead fish I have not seen a single white spot. Also, fish have not been scratching themselves, don´t they regularly do that with ich?

TheOtherGeoff, I will be getting an antibacterial if I lose another fish like this.

[LS6 Tommy]

Maybe they have had a mild infection all along and the increased CO2 aggravated the issue. I have had fish with blatant Ich not scratch, but the dashing about and then lying idle is very common.

Tommy