pop eye in a beta fish

Question
QUESTION: I have a beta fish in a 2.5 gallon tank. When I first moved him from the vase he was in to the tank he started acting slugggish and sick. I treated him with t.c capsules. He made a full recovery. However, he seemms to have pop eye and it will not clear up. I have treated him with maracyn a few times and have changed the water about 50- 75 percent each time. I have also replaced the charcoal in the filter monthly. He eats fine and swims around like he is happy. My husband suggested that i change the water too often and it becomes to oxygenated. I dont know what to do for him.

ANSWER: Hi Laurie,
 It is not possible to change the water too often.  Fish do best on water that is constantly changing (i.e., flow through systems), but few people can do that so we settle on weekly partial water changes.  You should be changing 25% of the water once a week, every week.  (By the way, constantly changing water is not the same as changing all the water at once which is something that you should NOT do).

 It is not possible for the water to have too much oxygen for a betta, unless you are doing something really bizarre like supersaturating ice cold water and then heating it instantly and putting it in the tank (which I assume you are not doing) and even then I doubt you could oversaturate the water.

 The problem is likely something much more simple.  What is the temperature in the tank, i.e., do you have a heater in the tank?  Bettas are tropical and prefer a temperature up near 80oF.  I find that many people email me about sluggish bettas at this time of year. The reason usually turns out to be that they have no heater in the betta tank and the air temp in the house is colder and hence the betta tank is colder and the fish shuts down (sort of like hibernating).

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>


---------- FOLLOW-UP ----------

QUESTION: The betta is not sluggish anymore. He is swimming around and eating. He does have the popeye condition though and it will not clear up. I put a thermometer in his tank  and it is  about 75-80 degrees. I attempted to put a heater in there but it will not fit because the tank has a top with a light on it. Should i be concerned about the popeye?

Answer
Hi Laurie,
 Popeye is always something to be concerned about.  There are various treatments that claim to deal with it but I have had little success with them.   

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>