My betta has popeye...help please

firstly, with such a small betta tank you need to be doing water changes more often than just once per week. if you are unable to upgrade to a larger tank, i would be changing at least 75% of the water on a daily basis. the ammonia produced by the fish builds up, and by the end of a week i'd be very concerned at the high ammonia level in a 1.5 gallon. much better if you could get a 5 or even a 10 gallon tank, with a filter and heater (25 watt heater for a 5 gallon tank and a 50 watt for a 10 gallon). bettas are tropical fish and require their water to be in the 76 to 80 F range. room temperature water is much too cool for them and they are more susceptible to disease when not kept at the right temperature.

also, are you using dechlorinator in his tank, and what brand?

popeye is an indicator that something else is going on in a fish's system. i would say the popeye in this case is due to stress from a high ammonia environment, combined with too cool a temperature. my action would be to get this betta into a more appropriate size tank with the correct temperature range, and keep the environment really clean (daily water changes) and monitor to see if that helps. it's not good to throw medications into a fish's tank when you don't know what exactly you are dealing with.

you say his tank is very clean, but you can't see the ammonia that builds up in a small tank that only gets a water change once a week. i'm assuming this is a betta bowl type setup with no filter? ammonia rises quickly in setups like that. i started out with betta bowls, and once i got my test kit (API Freshwater Master Kit), i was shocked at the ammonia levels in one of my 2 gallon bowls after a 100% water change just a few days prior! it was around 4 ppm! very toxic!

I would use Prime as your dechlorinator. many municipal water suppliers add chloramine to treat tap water, and most dechlorinators will only detoxify chlorine, not chloramine. Prime will detoxify chloramine. there is no need to have the water sit out before treating it and adding it to the tank if you use Prime.

do you have a thermometer in his bowl? without that, there is no way to know what the temperature is in there for him. i am quite confident he is too cold and stressed, especially if there is a/c running in the classroom on a regular basis.

when you get your water tested at the store, make sure they use a liquid drop test kit and not the dip strips (notorious for being inaccurate!). make sure they give you the actual test number results, not just 'your water is fine'. post those test results here on the forum.

i'd be picking up a larger tank, a heater, a filter, and a water test kit at the store when you get your water tested. those things will be the best investment for your betta.

He's a beauty! If it's only one eye, and your test shows 0 ammonia, he might have just injured it on something. If that's the case, clean water with some Epsom salt (1 tablespoon per 5 gallons) should clear it up in a few days. How is he reacting to the meds?

heating a small container like a 1.5 gallon betta bowl is dangerous IMO. the heater could fail and get stuck in the on position, essentially cooking your fish because the water volume is so small and the heat doesn't have a larger amount of water to disperse into. being as your little tank is plastic, the heater could melt it too. a larger tank IMO is definitely in order here for the health of your betta. you could go with a 5 gallon and the heater you just bought should be sufficient for it. a small hob (hang on back) or sponge filter will work well for a 5 gallon tank, and a filter is a necessity for a properly cycled and healthy tank.

your betta may be feeling the effects of the meds, and is lethargic due to that. i personally would not have medicated in this situation, but instead ensured the betta was in a clean environment along with daily water changes. from what i have read in this thread, it sounds like the betta is too cold, is stressed from ammonia in the tank, and is basically 'shocked' with each week's water change with clean living conditions all of a sudden.

as for the pet store employee saying you were changing the water too often....... ppppfffffftttt! (sorry, i had to). take a look back at my post in this thread where i mentioned how soon the ammonia climbed to 4 ppm in a 2 gallon bowl after a 100% water change - only a few days. small container betta bowls without filters like yours need daily water changes to keep that ammonia away. pet store employees very often have no idea what they are talking about and simply parrot the 'information' (i use that term very loosely) that they were taught/is in their store handbook. keep in mind, these stores will also sell you an oscar for your 10 gallon tank at home....... ugh.

you mention "all his levels were good". did you get the actual numbers from the ammonia, nitrite, nitrate, and ph tests from the pet store employee?

stress from the move could cause him to not want to eat. i wouldn't worry too much if he goes a day or two without eating.

he may have banged his mouth during transport, and it's a little sore? could explain holding it open after eating.

as for the fins, i would say it is fin rot - a common issue in bettas that are kept in unfiltered bowls with the water changed not frequently enough. if you are intent on keeping him in the 1.5 gallon, do daily water changes. best if those changes are 100% daily.