When you touch a betta fish do have to change the water?

It's not necessary to change the water just because you touched your betta fish. However, it's a good practice to wash your hands before and after handling your betta fish to minimize the risk of introducing any contaminants or bacteria into the water.

That being said, there are some situations when you might want to change the water after touching your betta fish:

* If your hands were dirty or contaminated with something that could be harmful to your fish, such as soap, lotion, or other chemicals.

* If you have a wound or infection on your hands that could potentially transfer bacteria to the water.

* If your betta fish shows any signs of stress or discomfort after you touched them, such as rapid breathing, clamped fins, or hiding behavior.

In these cases, it's best to err on the side of caution and change the water to ensure the health and safety of your betta fish.