Strange Angel Fish Sleeping Habits

[Fishmanic]

My angel once in a great while, when I turn the tank light on in the morning will be floating sideways tumbling or resting in the bottom of the tank. I think he's just sleeping or dreaming cause soon after he is alert and swimming normally. This youtube video shows exactly how my angel swims when this occurs first thing in the morning.

At All other times once awake he swims and acts normal.
Comments, opinions welcome

https/m.youtube.com/watch?v=GemJIEO9AFw

 

[fluttermoth]

It is extremely common for fish to become very disorientated at night; especially if the tank is dark and you switch the room lights on.
 
Don't forget that, in the wild, light changes happen only very slowly (sunset/sunrise/cloud etc) and the light is normally at a much higher angle (it's always from above, not the side in a river; because water finds the lowest level, the light doesn't penetrate the water very strongly until the sun is quite high), so fish can get 'confused' trying to right themselves.
 
When I started keeping fish, the advice was always that your room light should go on (or off) 10 minutes before (or after) the tank light does, so this disorientation/stress doesn't occur, although it's probably not harmful.

 

[Fishmanic]

the first time I saw the angel do this, I thought he taking his final breaths and headed to his demise. After a couple minutes, he uprighted himself and acted totally normal.

 

[fluttermoth]

the first time I saw the angel do this, I thought he taking his final breaths and headed to his demise. After a couple minutes, he uprighted himself and acted totally normal.

 
Yes; I once switched on the (bright) kitchen light and my tiger barbs were all slowly spinning down through the water like dead leaves; I was really worried but, like your angel, they soon righted themselves and were completely normal again.