How to properly perform a water change on a fish tank?

To properly perform a water change on a fish tank, follow these steps:

1. Prepare new water by treating it with a water conditioner to remove chlorine and other harmful chemicals.
2. Use a siphon to remove about 25-50 of the tank water, depending on the tank size and fish species.
3. Gently clean the substrate and decorations while siphoning out the water.
4. Slowly add the treated new water back into the tank to avoid shocking the fish.
5. Monitor the water parameters and adjust as needed to maintain a healthy environment for your fish.