Angelfish With Swimming Issues

[iBetta]

Hey everyone,
 
My Angelfish, Snorkel, has started having some swimming issues the past week and I'm unsure of the cause...
He tends to swim on his right side when he turns, and generally leans to the right when he is still.
About a month and a half ago, he had a sore left eye (and infection which I cleared up) so he could be blind in that eye, would that cause his swimming issues?
I've also thought it could be a swim bladder issue, but I'm unsure.
All his fins work well and have no damage.
He eats well also.
The water is clean, suitable temperature and has the proper pH, hardness etc. for Angelfish.
The filter flow also is not very strong.
 
If anyone could help me find out why he has problems swimming I would appreciate that very much.
Thanks in advance! 

 

[silenthawk2x3]

How tall is your tank? It may not seem exceedingly important, but angelfish need a taller tank in order to have space to move vertically in addition to moving from side to side. If they feel they don't have enough vertical space they often swim at an angle. When my angels hide under my curved driftwood they often sit at an angle and look like they are tilting when they swim or have something wrong. (They are nearly full grown and under the curve is between 8 and 12 inches tall.)

 

[iBetta]

Hmm not sure about the exact height of the tank, but tank size definitely isn't an issue.
After watching him a lot today, I'm almost positive he is blind in the left eye, so that might be causing these issues... 

 

[Lunar Jetman]

Hmm not sure about the exact height of the tank, but tank size definitely isn't an issue.
After watching him a lot today, I'm almost positive he is blind in the left eye, so that might be causing these issues... 

 
So what volume of water does your tank hold? Can you guess at the height?