Fish experience temporary blindness when lights go out?

[spicytofu]

I made a DIY LED fixture with an Arduino controlling Mean Well LDD controllers.

It is made of 24 Cree XM-L2 8000K Whites and 24 XR-E Royal Blue (new revised versions that handle 1500 mA)

It is definitely overkill if I run 1.5 A though them (duty cycle of 100%)

Right now, with no access to a PAR meter, I am using my eyes (not smart I know) to adjust the lighting. I set the whites to about 20% and blues to about 50% and its looks "well lit"

When I turn off the lights (I programmed it to slowly fade in/out), the fishes seem are swimming blind for a few minutes. I see them running to the the glass or swimming along the edges as a "guide rail"

After a few minutes, they start to swim fine and go about the tank.

Is this normal? Anyone experience this?

I have clowns and tangs for now.

 

[Sk8r]

Most sensory input depends on contrast in the environment in some degree, and if the curve is too sudden or steep, likely there's a period of 'from overload to nothing' just as you do when the lights go out and your senses see only black.

 

[spicytofu]

Most sensory input depends on contrast in the environment in some degree, and if the curve is too sudden or steep, likely there's a period of 'from overload to nothing' just as you do when the lights go out and your senses see only black.

Thanks, common sense would point to that, I just had to be sure. And since they have no iris, its worse for them

Im guessing could put extra stress on the fish? I have to be careful of the PBT I have in there.

 

[Sk8r]

You might go to the light and equipment forum and ask about adjustments. My kit ramps down to low, low blues before it goes out, and when I had MH, I had an actinic kit that would continue to provide blues for an hour after the main lights were out.