Fish Not Upright In The Dark!

[Teri]

(I hate having 2 think up topic titles)
I was peering into my tank last night, after i turned the light off, which I don't normally do because it's too hard to see anything, and all of the fishes except the cores and loaches, were listing to one side. All of them, even the tiny fry. As soon as I turned the light on, they all started swimming upright again. I don't know if they were asleep or not, they were actually swimmming around, so I'd say not, and I'd only just turned off the lights
They all seem happy enough, but do any one elses fish do this?

 

[Jozlyn]

LoL I've never looked at my fish after I've turned the light, prolly cause it's as dark as the ace of spades out here once you turn of the lights, might see if I can find a way to have a look later with just enough light for me to see them. Sounds really curious tho!

 

[paul_219]

THey probably go for a rest. They usually lay in the bottom of the tank to get some sleep.

 

[Ava_Banana]

What I have found is that they normally assume the light is coming from above the water.......soooo if you don't have the lights on, but have a light towards the front of the tank, some fish tend to slant that way.......it is more noticeable with the compressed types of fish (Dollars, Angels etc)....

When you were watching them....was there a tiny bit of light coming from behind you so that you could see them?

 

[Teri]

What I have found is that they normally assume the light is coming from above the water.......soooo if you don't have the lights on, but have a light towards the front of the tank, some fish tend to slant that way.......it is more noticeable with the compressed types of fish (Dollars, Angels etc)....

When you were watching them....was there a tiny bit of light coming from behind you so that you could see them?

Yes, the sitting room light was off, but the hall light on. I thought it might be something like that, some of the plants seem to be growing towards the front of the tank too, don't know if that's related in some way?
They look quite amusing, but I just wanted to check that it was normal fish behaviour! I don't suppose its doing them any harm? i don't really want to cover the tank when the lights are off, in case of over heating

 

[vinylman]

What I have found is that they normally assume the light is coming from above the water.......soooo if you don't have the lights on, but have a light towards the front of the tank, some fish tend to slant that way.......it is more noticeable with the compressed types of fish (Dollars, Angels etc)....

When you were watching them....was there a tiny bit of light coming from behind you so that you could see them?

I've read that Discus do that, too. Must be quite a sight.........

 

[modaz]

absolutely normal for fish to do this, the funniest to see is neon tetras, its like when the lights go off so do their braincells mine end up in the most strangest places due to floating almost upside down when its dark

 

[celaeno]

my rosy barbs also swim with their bodies at a slant as soon as i turn the lights off.

 

[highfire]

My golden barbs do exactly what you're describing.