I have a Betta and I 'quarantined' him in a small 2 gallon tank when I thought he was sick, and after his treatment, I began to notice he was building rather large bubble nests, and seems more relaxed than in my 20 gal. where he was constantly fighting his own reflection and the current (which I tried reducing as much as possible without jeopardizing aeration too much).
I've decided to keep him in the 2 gal, so I purchased a nano filter, and a nano heater for long term use. Now, before I decided to keep him in the 2 gal, there was no heat (room temp, 21C) and no filter. Essentially it was dead water. Now that there is a filter and heater, it should still be safe for him right? The addition of equipment shouldn't affect him negatively in any way, but the tank technically has to 'cycle'. Will my Betta be ok? I'm feeding him bit by bit until he stops eating, and I'm doing regular water changes.