Betta - Fishsitting Disaster!!!

Question
I was fishsitting for my roommate. She came back yesterday. She was really upset because now her Betta has something wrong with BOTH of his eyes. I didn't notice it before he seemed fine until just a few hours before she came home. His eyes are bulging out! She checked the temperature. Unsure what else to do she changed the water. The water was a little dirty - she changed it right before she left she was gone for 7 days. I looked at some pictures online and I think he might have popeye. He doesn't seem to have any other symptoms associated w/ popeye. He is still eatting. He is a few months old. She keeps him in a vase. She doesn't have any other fish. She feeds him 5 pellets a day and occasionally some dried worms. I don't want him to suffer, but is there anything I can give him that might help him get better? I looked up some things on-line but I'm not sure which one is the best option: Ampicillin, Tetracycline, Mardel Maracyn, Mardel Maracyn-Two...

Answer
Hi Ariel
One of the best thing's your friend can do for the betta, is upgrade him to a larger tank/bowl.  I personally don't recommend anything less then 5 gallons-doesn't have to have a filter either.  At the very least, an upgrade to 2 gallons would be better then the vase.  

You're right, it does sound like it's popeye.  The popeye was most likely caused by the poor water conditions during that time, especially if no water changes were done.  For a 2 gallon tank, I would recommend changing out about 50% of the water every 2-3 days.  For a vase or other small container, it should have a 100% water change every day to every other day.  That's just to give you an idea of how often the water changes should be done on an unfiltered tank.

Best thing to do, keep the water quality excellent by doing those frequent water changes.  A little epsom salt(not aquarium salt) can be added to the water-epsom salt helps draw fluids out.  I would say a small amount, about 1/8 tsp or less depending on how large/small the vase is.

Medicine wise, I would go with either Maracyn Two or Maracyn Plus.  Most diseases and bacterial infections freshwater fish get are caused by a gram negative bacteria, and both of those meds will treat that.  I would hold off on the meds for a day or two though, and see if the water changes help first.  A lot of times just that simple step is enough for fish to "cure themselves" so to say.

Hope that helps, and good luck!  Let me know if you have more questions!

Christy