Betta Frank with Eye Bulge

Question
QUESTION: My little Frank has one eye buldging and it will not get any better.  He lives alone (of course) in a 5 gallon tank that has a filter that doesn't cause turbulence in the water.  I do 100% water changes every 10 days.  

I have tried Marcyn 2 and Tetracycline drops, and nothing has changed. How should I proceed?  All of the tests are within range...not sure what to do to help him.  Is it painful for him?

I feed him twice daily--once with HBH Betta Bites and once with HBH ColorBright flakes, which he loves the most. He still has a healthy appetite for the most part. He is swimming around occassionally, but keeps resting inside his surf hut more often.

ANSWER: Hi Rachelle,
Poor little Frank.  Popeye is very hard to cure, because we do not always know the reason why it occurs.
Popeye can be caused by lack of vitamin "A" which is why it is always better to feed a betta different food such as Betta Flakes, Daphnia, Bloodworms, Plankton flakes, etc.  Feed him twice a day in small amounts, such as:  2 pellets for one meal..His tummy is the size of his eye, we should always remember this when feeding him.  He should have one frozen cooked pea a week with the outer layer removed.  Cut the pea into tiny pieces, and feed this to your betta.  This is to prevent constipation which leads to Swim Bladder Disease, and the pea cleans out his system.  On the day you feed him the pea, do not feed him anything else.  
For now, feeding him anti-bacterial medicated food may help him.  You may also add 2 teaspoons of diluted aquarium salt to his water.
He could have a tumor, which may or may not be cancerous, but this is rare.  If so, there is nothing you can do except keep his water very clean.  Change all the water once a week.
If it is a bacterial infection, or Gas Embolism it is often cured with penicillin or amoxicillin.  Feed him the anti-bacterial food with this treatment also, and add the salt.
Later, when he is better, feed him food that have Vitamin A such as Bloodworms, Glass Worms, alternating with good quality food so that he will get all the vitamins he needs.  Good diet, and clean water are the best medication for keeping fish healthy.
I would also like to mention in case he doesn't have a heater, his water should be 80 degrees.  Bettas need warm water.  If his water is lower than 78 degrees, bring his temperature up, but do this very very slowly as bringing up the temperature to fast would be deadly.  Raise it one degree every two days.  This would help him too.  He is a tropical fish, and tropical fish need heated water.  In cool waters they are cold, and get sick.
I hope that little Frank pulls through, and if you have any questions, please, do not hesitate to write me again.
Lynda

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

QUESTION: Even with a filter on the tank I should still be doing weekly changes...I was told that changing the water too much could be tramatizing for him. Is this not true?

So I cut my water changes to 10 days rather than the 7 I was doing originally.  Could this be what has made him sick?  My tests were all within range and I am about 4 days out from the next water change.

Answer
There is one thing I don't understand.  If you are using a filter, and doing 100% water changes, then your tank water hasn't cycled.  You really don't need a filter in that case.  You may use your filter without the carbon when medicating so that the medication goes through all the water in a tank.  Bettas do best without filters.  If you are testing your water, then you know if the ammonia level is zero, and nitrite level is zero.  You could wait 10 days if this is the case.  I do mine every 7 days, but I really don't see how 3 more days could hurt if there is no ammonia or nitrites in your water.  Also, water changes are good for them, if you are using a good water conditioner such as stress coat, or aquasafe.  
He should be medicated as soon as possible.  Do a complete water change before medicating him.  This will not stress him, it can only do him some good.
Lynda