Just the filter
I was feeding freeze dried bloodworms until I found out they were not a staple food. He last ate 9 days ago, on Friday, October 5. Since then, I've tried frozen bloodworms, brine shrimp, pellets, and now Bio Gold pellets (but he's not coming to the top of the tank, even if he does smell them).
I used to feed him daily, about six days a week.
New tank yesterday - 100% water change. Purified water with Tetra BettaSafe water conditioner - 7 drops/gallon. I also added 2 drops of Stress Coat. When he was in the small tank, I changed his water 2-3 X/week.
I have not tested the new tank water. I was bringing samples to Petco for them to test prior to the new tank. On Friday it was: 7.1/neutral for pH, zero for most of the others, and .5 for ammonia (which he said was in the safe zone).
No change in appearance - he's still beautiful.
Not swimming at all and laying on bottom of tank.
Monday, October 8 - his fins were clumped and he wouldn't recognize me or eat.
Bigger tank, water changes, trying to entice him to eat.
No history of illness that I know of.
I have had him since May 16, not sure how old he was before that.