Tinfoil Barbs & Parrot Fish Water Conditions

Question
I'm new to the aquarium world and I'd like some help on how to maintain there water properly. I read that they like acidic to neutral water. How do I accomplish this?  

Answer
Hi,
Adding a piece of bog or root wood from a petstore is the easiest way to do this. The natural tannins lower the pH and hardness and add for a really nice look in the tank. Just a warning, the tannins can turn the water a brow color, this isn't a bad thing though, that actually means it's working because the tannins are being released into the water. A carbon filter and water changes can minimize this effect if you don't like it.