You guys just about summed it up for me. That seems pretty basic when put in that way. Hopefully all of the technical stuff becomes more clearer though in time. But if you pick fish based on the local water supply, how limited is the possible fish selection? Aren't there quite a few fish for every water parameter? Thanks for the help.
Yes, it's a matter of fish mix though. Picking fish based on similar parameters gets harder the more fish you try to squeeze in and there is the temperament to deal with, some long finned sedate fish can't be with active fish or fish that might be prone to fin nipping or aggressive behaviour.
I have a set of issues to deal with between really hard water, higher pH, warmer temperatures and particular fish issues that reduced my list to about 10 fish. I think Byron has somewhere over 20 species in one of his tanks but his water is really soft with a low pH which lends itself well to more fish.
Basically, go through the fish profiles and compile a list that fit your water parameters and tank size. If you have a favourite fish that you want first, jot down all the parameters for that fish (pH, hardness, temperature, tank size) then go through and list the fist that have very similar needs. Then eliminate ones that are not a good temperament match.
It may take a little time but it will pay off big when you don't have to mess with the water and you don't have issues between fish to deal with. There are enough things to worry about when things are going right with a new tank that you don't want avoidable issues cropping up to really complicate things.
Jeff.