The chances of your tap water having a ph which won't grow plants is very small, nothing to worry about. I think its better to find fish that like the ph of your water than try to pick the fish first and then make the water fit.I am totally lost when it comes to water chemistry. im new to this planted aquarium thing. i've never test my water before. Im planning to get a water testing kit, but the thing is how do i know what im reading and how would i know if its at the right level for my plants and fish. And what does the numbers mean
High ph water will tend to be very hard, meaning it has a lot of dissolved solids in it, mostly calcium and magnesium. Pure water is soft.
Fish waste leads to ammonia which gets converted to nitrites and nitrates. Ammonia and nitrite are poisonous to fish, nitrate is poisonous but it takes so much nitrate to kill a fish that most people don't worry about it. If you have plants in the tank they absorb the nitrates for you. Its because of ammonia, nitrites and nitrates that you have to limit how many fish you put in the tank.
I would do things this way:
1. find out your tap water ph by testing it or checking on the internet.
2. Correctly cycle your tank as directed in the standard Nitrogen Cycle advice.
3. buy fish which prefer the ph range of your tap water.
4. limit yourself to one inch of fish per gallon of water. Snails need more than a gallon per inch and shrimp need less than a gallon per inch.
5. Since you bought fish that prefer your tap water's ph all you need to do is test for ammonia. If it gets too high do a water change and hold off on feeding the fish until it goes down to near zero.
I think those five things are enough.