For the life of your fish.....please type in Betta fish, on the web search bar, and all sorts of sites will pop up and educate you on the care of your fish.

1) Don't ever use any chemicals like bleach or dish soap to clean his tank. That will kill the fish.

2) You have to de-chlorinate tap water.

3) Do not just dump a fish into other water without floating them in......You can use a new plastic baggie (ziplock), put the fish and some of his water in the bag. Seal the bag and make sure there's some air in there for him to breathe. Then stick the ziplock bag into the new water and let the fish get used to the temp of the new water (about 15 minutes in water that's between 75 and 82 degrees), then gently pour him into the new water.

4) Betta's like to hide so if your tank can accommodate a small ornament or plants, they will feel less stressed out.

Hi Say What?, Have a look at this link for the sake of your poor fish, he's just been exposed to many of the worst dangers a fish can have & yes the tap water was one of them. I know you didn't intend to hurt him but I hope you have some treated water to keep him in. Please do your research, he's a living being with feelings & deserves respect.