My vote would have to go to anaerobic substrate. I have had similar outbreaks in the past where suddenly, a dozen or more fish (in my case ancistrus) are found dead while cardinal tetras are happily swimming about. My theory is (and it is only a theory) that pockets of hydrogen sulphide and possibly methane formed in the substrate. The were dislodged by the fish scavenging for food and poisoned the fish. The tetras are either less susceptible or the gas diffused enough by the time that it reached them that it did not harm them. I could also be convinced that there had been a build-up of carbon dioxide. In that case, the tetras might be just that much less sensitive. I used to believe that apistos were impossible to keep. The turning point for me was when I bought some locally bred ones from my local fish club. I couldn't believe the difference. Now I buy local when I can and when I cannot, I go to one of the better LFS in town (I actually have a choice) where the tanks are individually filtered and the parasites are not shared between many tanks, and I look for the best fish that I can find which I then quarantine for several months and then release into my community tanks. Good luck, and don't give up on the dwarf cichlids. Doug "Maladorno, Dionigi {DRUG~Nutley}" wrote: > "Alysoun McLaughlin" wrote: <<< > Failure keeping cichlids in the long term > > Ok, I'm stumped. > > I've had a planted community tank set up in my living room for about two > years now. It's a healthy environment -- or at least, it seems to be for > the plants and for certain fish. But I just can't keep cichlids or > labyrinth fish. > [snipped] ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!