The bowl is fairly large (you can see it in the picture below)
I usually do 1 water change a week.
I have a green scooper thing with a net on it and I scoop out my betta and put him in a large bowl with water that is the same temperature as his normal bowl's water. I then dump all of my betta's bowl's water into the sink, clean the bowl and the rocks, and then dry the bowl and the rocks, dump some new water into the bowl, and dump my betta back in. All water used is bottled water... it's "Real Canadian Natural Spring Water" if that matters.
I read somewhere that you're supposed to only change 25% of the water, but I don't see the point because the "dirt" or whatever will just mix in with the new water that you put in anyway, but maybe I'm wrong.
I don't see any fungus or anything on his body, though I don't really know what to look for since this is my first fish. His fins seem to be normal, and for the few seconds that he does move around he flares a bit.
Here are two pictures...the first one shows him in his bowl, and the second is a close up of him.
Sorry they're so blurry...It's hard with a 2.2 megapixel camera.
http/a.1asphost.com/aDcOoL/Bowl.png
http/a.1asphost.com/aDcOoL/closeup.png
Most people have given you advice about the size of your bowl. I cannot access the pictures, but am concerned about your cleaning routine and water stats.
You are giving him 3 different types of water to sit in in a very short time. His tank water, the new bowl of water, then fresh water from the bottle. Very stressful.
Why don't you leave him in his bowl and do more frequent but smaller changes and use a gravel hose- vaccuuming/ stirring the bottom of the bowl ?
Do you add a water treatment to your water? I don't use bottled water, just stand it for 24hours (to get rid of chlorine) then add Tetra Aqua or similar.
Do you check the water chemistry of your bowl? Nitrate? Nitirite? Ammonia and pH? This is vital for good fish health.
What are you washing the bowl and rocks in? These surfaces are covered in the 'good' bacteria which maintain the biological balance in your bowl- destroying ammonia and nitrite. If you use ordinary tap water then you will destroy them. 100% water changes will also affect the nitrogen cycle in your bowl. Look that up under 'search' if you need to.
If you must wash rocks ( I wouldn't), use the water that you've just taken out. It won't be that dirty, plus it has beneficial bacteria in it.
PS. I've also just read some of the symptoms you've described eg. tail down. This may be swim bladder- brought on by poor water quality. Also fungus can be brought on by scale damage eg. too much handling. I've used esHA 2000 successfully for the fungus. I've not been successfull in treating swim bladder. However, improvements can occur when the water quality is better. Check your stats!