mimiheart
Aquarium Advice Freak
The bettas in pet stores are such mistreated animals! Do they even clean that water?!
Probably depends on the store. You can tell by looking at the water and the fish, though. If the water is dirty/cloudy, it hasn't been cleaned. Bettas aren't the cleanest fish out there, the water will get dirty. Also, the cups shouldn't be air tight, so it will evaporate, and there should be a water line on there. I've watched him clean the water in the betta cups and do maintenance on the large tanks. He won't sell sick fish. OTOH, one of the lfs near me is probably a great place to get reptiles, but has told my friend things that are just downright false. Every fish she's gotten from them has died within days. And their bettas are all horribly looked after.
When I looked for bettas, I ended up going to two different big stores. The one that had the .5 quart sign, and the other big store with the guy I know. The bettas were all active in their cups. There was no excess food in them (unlike at the other store, where there were quite a few cups with very low water and with 10-15 pellets sitting at the bottom). Some were blowing bubbles, which is good. None had faded colors. Some flared at me. They aren't going to be super active in cups that size, but they should wake up and swim around and be interested in events happening around them.
Talk to the people who work there. Ask how often they clean the water in the cups. If you see a lot of low/dirty water, walk away. You may end up with a sick fish.