George, I know of no fish that can live in pure R/O water. I'd suggest adding some peat extract to the water to give it some "body" if you don't add a little tap water. There are many fish that can handle extremely soft water. I'd think any species from the Rio Negro should be OK. Actually, nearly all Amazonian species will do well in extremely soft water. Mike Wise "Morris, George" wrote: > Greetings from the newest member of the list. I've been breeing > tropical fish since the late fifties, but I've mostly stayed away from the > rain forest fish since it's so much hassle to maintain the necessry water > quality/ chemistry. The company I work for is considering putting an > aquarium in the waste water treatment room as a sort of demonstration of > water quality for visitors. I've been asked for advise on the kinds of fish > they could use and the biggest problem I can see, and it's a big one, is > that the water is too pure. The last step in the process is RO. I think > they will have to mix in some tap water, but I wonder if anyone out there > can suggest some rain forest cichlids that like REALLY soft water. > Regards, > George Morris > > ------------------------------------------------------------------------- > 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"! ------------------------------------------------------------------------- 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"!