Breeding and PH

Unfortunately, pH is very important for successful incubation of eggs. Most fish eggs will not succeed in a pH that is very far from their native conditions--while the juvenile and adult fish are adaptable, the eggs are often very sensitive to pH. If you want to breed the softer water fish, you can give it a try in your water conditions, and see how it goes. If the fish successfully spawn, but the eggs don't hatch, then you might want to modify water for them. This can be done, it's just not something to take lightly and go at haphazardly. There are methods which will result in stable, low pH water that is similar to naturally occurring low pH waters--but commercial additives and chemicals will seldom work. Various filtrations, from RO to peat, are better, though can be costly.

While I agree completely with OG's comments, I would like to expand or clarify on them a bit. Despite all the massive postings on pH on the boards, fish do no 'read' pH, they are aware of TDS (total dissolved solids) and of particular classes of ions, not pH. Many of the buffers, exchangers etc. which are sold to "modify" pH do little for TDS, or actually increase the TDS, which is usually contrary to the desired goal. This is why peat absorbtion of dissolved minerals (done outside the tank, with the treated water being added to the tank after treatment) or RO or RO/DI are the best paths for water modification - these process all do remove minerals from the water, where buffers and such add minerals to the water.

OG was also correct on the much greater sensitivity of egg membranes to mineral content that fish sensitivity to the same parameters. Blackwater or softwater fish egg membranes are in particularly sensitive to calcium and magnesium ions in the water (this is why the reports on softwater fish breeding use GH - which is a measure of these ions in particular). Those ions especially tend to "tan" or toughen or harden those membranes, blocking frertilization, or hatching if the eggs have been fertilized.

So the first requirement is to decide what fish in particular is to be bred, then to research just what water modification that fish needs, if any. Next is to determine which process will provide you with the required water.

HTH

My tap water is 7.5pH and 180ppm TDS. I have bred well over 200 different species of aquarium fish in that same water. Only when it came to Discus, a few Apistogramma, 1 Taeniacara & 1 Ctenopama I quickly switched to RO water as I never had viable fry from those few. In my fishroom I found that TDS is much more important than pH. My suggestion is to try to breed any of your fish in your normal water and then if you get no results you can try to adjust. I even hear that today Discus are being bred in much harder water than they needed only a few years ago. Don't get involved in changing everything until absolutely necessary. Just my view on breeding. Using an RO unit, the pH will drop but only slightly.

Thank you Z Man!