This proved to be the biggest mistake! I immediately saw a change in his behaviour, gradual at first but then rapidly!!
His activity became slower, he didn't respond to my whistling as eagerly and he spent a lot of time just THERE not here AND there, but just THERE. I thought that maybe his water was dirty and I made the water changes more frequent but even then he just didn't do anything anymore.
What really worried me was when I noticed more and more fish food lying at the bottom of the tank. This NEVER happened. He didn't even show any signs of stress when I made a shaking movement with the jar!
When I tested the water temperature (I STUCK MY FINGER IN), the water was COLD! like ice and I immediately knew the cause of the sudden decline in General's activity. Placing a heater close to his tank didn't really help and despite the fact that Bettas are really tough fish I didn't think I would be having General Fin with me much longer and I was right.
I returned home from Campus one afternoon finding my dear beloved fishy pal floating... I considered CPR... but uhmm... don't think it would've worked.