My friend's on vacation at the moment, so I'm taking care of her betta. This afternoon, he wasn't swimming around like he usually was, and seemed a bit pale around the gills and front fins. He ate his food, but still seems lethargic and pale. Do I have a problem?
The container's a small vase, not sure of capacity. Water was last changed a few days ago, just before she brought him over. No heater, no filter. He gets fed twice a day, a small pinch of food each time. Not sure about water conditioner. I've taken care of him once before and he was fine that time.
If it is small, like less then a gallon then the water needs to be changed often. I'd say about ever other day or so.
I highly suggest that the Betta get moved to something that is at least 2 gallons (not sure if your friend would go for that).
Do a 100% water change and use water conditioner.
Oh, and is the water around 78-80 degrees? That's where it needs to be since Betta are tropical fish.