Very sick betta...what do I do?!

Question
I know this is terrible, but I had accidently left my betta in my dorm room for two weeks and i couldn't go back because I live outta state. I just got back to him and he is still alive, but kinda sits on the bottom of the tank vertically, like he is sitting on a chair. What can I do to help him?

Answer
The FASTEST thing to do and do it NOW if you haven't already (caps for emphasis only) is CHANGE THE WATER!!  You do not say what he is in, but if it's a little container, get a small box of aquarium salt and add about 1/4 tsp. to the water when you put the water back in. This will help his gills in case he has ammonia poisoning. If you have a bigger tank, follow the directions on the box.  If you cannot get aquarium salt, you can use NON-iodized table salt for this. Add the same amount.

He probably has ammonia poisoning.  If he's in one of those small little tanks, you really need to change out the water weekly and put new water with the water conditioner back in.  Also a pinch of salt would be good (each time).

I hope this helps.  You should see some improvement shortly thereafter.  Let me know how you make out!

Good luck!!