I was away for 2 weeks and the water for my betta was not changed. Now it is limp and can barely swim. It is at the bottom of the tank and appears to be totally disoriented. I changed th water, but it has been 12 hours and it has barely moved (still alive though). Can anything be done?
I would change 1/2 of the water again, and make sure the temp is the same as his tank temp. If you don't have him in a heated filtered tank, then I would seriously think about getting one. Bettas get sick more often in cold water. I don't know how long you have been keeping bettas so this may just be old news. I hope your betta baby perks up.
Is your Betta is a heated, filtered, cycled tank of 5 gallons or more or is he in a bowl/vase/tiny plastic box Betta Kit?
If he is not in a tank and the water has not been changed for 2 weeks he is probably suffering from ammonia poisoning. He may be too far gone to survive but if he is in a bowl/vase etc. and not in a proper tank then he needs a 100% water change with properly dechlorinated water and antibiotics such as Maracyn-Two.
If he is in a tank that is cycled and his water parameters are testing as zero then treat with Maracyn-Two and Maracyn as he probably has some type of internal infection and these two meds will cover a broad range of problems.
Either way unless he gets antibiotics right away he will probably die. When Bettas are this sick they cannot wait even until tomorrow to get meds.