I would have re-bumped your topic for this question, just helpful for those who may have assisted you before.
Here it is for those interested: http://www.bettafish.com/showthread.php?t=82375
First question, has the bloating cleared up?
Bettas go when they need to, and quite honestly I havent seen my two guys go ever. But they do, it's just very hidden I suppose.
If the bloating has cleared up, there will be no need to continue with ES treatment. If you are unsure - pictures of him currently will assist us greatly in ascertaining if he is still.
Providing everything is cleared up, and your tank is now cleared too. A basic introduction into the main tank is required.
1. Retrieve your new betta from wherever you kept it. If you had it in a sink, wash its cup or bag thoroughly (no soap!) but gently to get anything off from the sink you can. Place your betta to “bob” in the tank at the top. Note: If in a cup (which should have holes at the top), make sure the cup does not sink! Keep it upright to avoid drowning your friend.
2. Allow your betta to “bob” for about 5 minutes to get used to the temperature of the tank. After 5 minutes, add a small amount of the new tank’s water to its cup to “acclimate” to it.
3. Repeat this step at least 2 more times for at least 10 or so minutes. If you do not, you run the risk of killing your fish due to shock. The longer, the better! Try for a half hour.
4. Now comes a potentially tricky part- have paper towels on hand! Remove your bettas cup from bobbing. You can do this one of two ways:
a. Netting method: This method requires you to carefully hold the (cleaned!) net over a sink and gently pour out some of the cup’s water, being careful not to drop the betta out. Aim to get as many nasties out as you can. With some water still in the cup, pour the water and betta into the net gently, so it falls softly in the net and the water leaves. Gently place the net into the tank and let it swim out gently.
b. Cup method: Carefully drain a large amount of the cup’s water out into a sink, without letting your fish fall out. Return to the tank with a little water left in the cup and plop the betta in- avoid letting as much icky cup water in as possible!
*Credit to PewPewPew for the above, Day One write up segment for introduction into a new tank