I have a petco King betta named Gus. He lives in a like 1.5 or 2gal tank, where I do one 1/2 and one full water change (where I wash off the gravel and plants) with distilled water a week.
I have had him just over a month, he is usually pretty active, he swims around, fights his reflection, leaps around and dances for food, etc.
All of a sudden like two or three days ago he stopped being at all active. He sits near the top completely motionless and does not wiggle at all when I come up (he usually gets super excited cause he knows I bring the food). And if I just drop food in he doesn't seem to notice. However, if I tap on the glass or wiggle his plant and "wake him up" and then feed him he jumps at his food and eats voraciously. If within that couple minute time span where I have just woken him up and fed him i show him a mirror he fights his reflection like normal. However, once I walk away he goes back to the like catatonic state and if I hold a mirror near him (he usually chooses a place near his plant right near the front of his tank to "sleep") he does not notice or fight at all.
Am I being needlessly worried? Has he just settled in, gotten bored of his surroundings, and taken to very long naps, or is this behavior a precursor to some sort of illness I can prevent? Also, if it is at all relevent, his color is very good still - (I had a betta many years ago who I had for two years and then he passed away, right before he did he lost his color...)