So i got a new 5gallon tank for my betta (that's lived through it all). after his 2.5 gallon tank cracked. After i cycled the tank for a week and put him in (let the temp adjust in a little ball i have). The filter was too strong, so i turned that off, but have since got a filter sponge to relieve the current. However, a day or two after i noticed he was very slow and weak. he almost swims on his side where before he'd be quick to anything and would flare his gills at me as soon as i stepped near him.
I'm not really quite sure what to do, should i put him in a QT tank? He's just getting worse in the 5gallon.