That just depends on the kind of fish. Some fish like tetras need acidic water with a low pH meaning the water is more acidic. Some fish need basic water meaning it has a higher pH. There is no hard an fast rule, you have to research the individual species to find out what pH range is best suited to that species. That number is usually based on the type of water conditions found where the species grows in the wild.
2.0 to 4.0 i thank
pH 9-10
pH 9-10
When setting up an aquarium we must allways try and simulate the fish's natural environment as best as possible. If a fish is found in water with a PH range of 6.0 - 7.0 that will be the range we would try and keep with-in an aquarium. As for the question "Why should the pH for tropical fish be 7" that is a bit of a trick question as different tropical fish have different PH ranges. www.justaddwateraquariums.com.au
7.35 - 7.45
Normal pH level is around 5.5-6.5,anything higher than 7 can b deadly to ur aquarium,fish stores usually sell a few different products to reduce or increase ur pH value such as PH MINUS.
The pH for a aquarium is 5-7
Api Wardly.
blood needs to stay a a certain ph otherwise you body is not healthy and might fail on you.
Acidophiles do best in an environment with a pH of 3 or less.
Enzimes are sensitive to pH and function best across a narrow range of pH.
My junk
Most enzymes work best at a certain pH, however there are some enzymes that can operate over a broad pH range.
A low pH can cause the calcium carbonate shells of snails to deteriorate, and eventually kill the snails. A pH of 7.0+ is best.