Aquarium light scaring the fish

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Aquarium Advice Newbie
Jan 25, 2024

I have a little problem with my fish getting scared of sudden light turning on inside the aquarium.

My five banded barbs and serpae tetra hide or swim at the bottom when the lights turn on. Most of them are not very active so they mostly stay at one place.
As soon as the light turn off, they come out and are all over the place.

I've tried to cover one of the two led lights to dim it a little bit togheter with floating plants. It doesn't seem to help.

I belive its the sudden light that scares them but I can't come up with an idea on how to fix to problem.

It's a shame to have almost 30 fish in 125 litres tank and not being able to see half of them. It looks empty.

I hope there is someone who can help solving this issue.

Thanks in advance
Have you tried turning on the room light half an hour (or opening the curtain) before the aquarium lights come on to ensure they dont go from darkness to sudden light?

Some lights are programmable, with sunrise/ sunset settings. So the light gradually ramps up over an hour or two, and at the other end gradually dims. Fluval aquasky light fixtures do this. Can you change the light to a programmable one?
The room has daylight at least 4 hours before the lights turn on in the aquarium.

I have a Juwel aquarium so i think there shouldn't be any problem changing the light.
I will give it shot with a programmable light as you metioned.
Thank you.
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