my roommate brought home a betta that has popeye. i have already begun treatment with maracyn-plus. it lives in a vase w/water plant roots hanging down into 3/4 of a gal water. she said that the owner does a 60-70% water change every two weeks and uses distilled water. is this good? present water params are:
ph-6.4(too low?)
buff capacity-0(too low?)
hardness-0
nitrate-0
nitrite-0
ammonia-0
What do you think could be the cause of the popeye?(its only one eye)

well, after an extensive search, i found some very good information on bettas!
it seems that i should never use distilled water because it is too soft and contains no minerals. i am now going to ween "him" over to bottled water.
i am also going to switch his container to a large brandy snifter as well.
the water plant w/roots hanging in the water are gone. when i get the snifter i will purchase a submerged water plant for decor/hiding spot.

Distilled water, used alone, will usually kill fish. The pH will swing like crazy, due to the amount of dissolved gasses, and the wastes being produced, and all kinds of things.

Why aren't you using your tap water? If you use a dechlorinator, tap water is really the best choice. Test the pH of your tap water, and if it's between 6.5 and 9, it's fine for a betta!

Good luck with this guy! They love plants to swim around in. Another good thing is that they don't eat plants (they're carnivores) so they'll never destroy a pretty planted tank like some fish will (*cough*goldfish*cough* lol).

i do use a dechlorinator for my gf water. i amgoing to start using my tap water. thank you for the reply!

some Lfs sell a type of bottled minerals for your tank... i unfortunatly dont have mine with me so i can't give too many details but i think it's Kent fresh water minerals... it doesnt contain nitraits, and it has worked pretty well in my tanks... i hope this helps you a little bit, if u wanted to go a different route

Be sure to cover the brandy snifter with a net or mesh because they can jump. Sometimes one eye will pop out due to an injury. Just so you know, I believe bettas do much better in actual aquariums than small bowls/vases. Having a heated, filtered, cycled tank is really the best for them. I have all 4 of mine in aquariums and they are active and healthy. Just my two cents.