We gave my son a dark blue crowntail betta on his birthday this year, and so far (two months) everything has been going well.

The betta (Marshmallow) is in a one gallon fish bowl, we do a 100% water change weekly, and use the filtered water from our refrigerator treated with Top Fin Betta Water Conditioner (we let it sit out, covered, to reach room temperature beforehand). He is fed once daily with National Geographic betta flakes.

Last night and today, Marshmallow has been alternately lethargic and frantically darting around. He will float at the top of the water for a while (long enough for my son to burst into tears thinking Marshmallow died), and then suddenly swim around for a few seconds. When fed today, he ate a couple of bites of his food and then lost interest. His eyes are also bulging, one more than the other, and he has some sort of light film around the tail end of his body--not white patches like ich, but more of a sheen. I shone a flashlight on him and couldn't really tell if it might be velvet or just normal slime coat.

So today, I have put him into a smaller bowl while we clean and disinfect his bowl--his bowl, glass rocks, and plants are all air-drying after a thorough wash with antibacterial soap and rubbing alcohol (I don't keep bleach in the house). It's only been five days since his last water change. I've sent my husband out for water test strips, aquarium salt, and a small heater. Since being moved to the smaller bowl with freshly treated water, he's been more lively and flaring his fins and gills out at his reflection. At first I was afraid he was suffocating!

I realize that we have probably been doing quite a few things wrong...when we bought Marshmallow and his little bowl, we were under the impression that bettas are perfectly happy in little bowls with no filters, and the pet store associate assured us we didn't need aquarium salt or a heater down here in sunny Florida. Now after reading (lots) of forum posts online, I'm not so sure all of that is true.

I'd just like to know if we are taking the best steps to improve his environment right now, and what routine care we should really be providing... Should we be adding aquarium salt with each water change? Are there medications or other treatments that we need to add besides the water conditioner? Do we need to do water changes more often?

Thanks in advance, and sorry (to readers and to poor Marshmallow) for being so clueless....!!

(Went back to put in the photos I forgot...the camera really shows more worrisome physical characteristics than I can actually see just looking at him.)

Update: Have placed Marshmallow in his cleaned bowl with BettaFix and half a teaspoon of aquarium salt well-mixed with the filtered water already treated with conditioner. He is still darting around the tank in short bursts of speed.