I'm new to the site and new to keeping fish.
I brought home a Betta about 4 hours ago. Was given a whole setup today as the lady couldn't look after them. They belonged to her son who went away to school. There is 3 fish, the Betta and I believe the others are a Otocinclus, and a Corydoras. The tank is a 5 gallon, with filter, air stone and heated.
The Betta was just hiding in a bottom corner when I picked them up and the lady said it had been like that since it moved to her house 10 days earlier. I've since removed the air stone and put a baffle on the filter. Heater was set to 78 degrees, so I left that. I did use a new razor to clean a bunch of the algae off the sides of the aquarium as it was pretty bad. I haven't changed any water yet, as I'm just now sure how much to change. The Betta is now out from the corner and swimming around. He/She had no problem eating when I feed it 2 small pellets of Betta food. The tail fins or whatever they're called don't look like any of the pictures I've looked at. They're all limp and folded over.
Here is a picture I just took of it. I think it's a male, but I'm not sure.