my bannerfish is purposely hitting the tank cover, antbody know why?

[Raye]

right now he is laying exhausted, this started yesterday. had him for about 4 months, since a baby.

 

[melosu58]

Their care level rating is easy but they require at least a 125 gallon tank. That picture does not look good. What does your water test results say?

 

[Raye]

my ph is 7.8, alk is 180, nitrate 20, nitrite 0' salinity is 1.025. tank is a 55gl