Your nitrates are to high. I would do a 50% water change and then retest. Stop feeding him for now and stop leaving food in the tank. What temp do you have it at and how often are you cleaning and doing water changes.
A 20G is way to small for a fish that size which is probably why you are having issues in the first place. That fish should be in nothing less than a 55G. It also appears he has some gill curl going on and that due to poor living conditions.
A 20G is way to small for a fish that size which is probably why you are having issues in the first place. That fish should be in nothing less than a 55G. It also appears he has some gill curl going on and that due to poor living conditions.
