Angel Sitting Vertically At The Bottom Of Tank

[regimail]

Today morning I saw my angel vertical at the top of my tank. As I was in hurry I did not pay any attention. When I can back in the evening I saw it sitting at the bottom of the tank again in vertical position and almost lifeless with its mouth constantly open as you can see from the picture.
One thing I noticed is that its colour is darker than usual. I am not sure what’s wrong with it. For now I have moved it to another tank. I have not used any medication as I am not sure what is wrong with it. Does Angels have swim bladder disease? I have medication for it.
Water parameters are normal. I do a 15-20% water change every week. Last water change was done on Sunday.

Here is the image of the Angel.

 

[Tortea]

I think its swim bladder, but is it only upright/still or is it very wobbly?


Tortea

 

[regimail]

I think its swim bladder, but is it only upright/still or is it very wobbly?


Tortea

It was upright still, not wobbly. Now its down on the floor. I think it is going to die.

 

[WILDER]

Your tanks severely overstocked.

What are your water stats in ammonia, nitrite, nitrate, and ph.
What do you feed the fish.

It sounds bacterial to me. I would add a bacterial med.

Is that a pinky brown dark patch below his gill.