Tetra Fish and Lighting

Question
Hi,

I have a 20 gallon fish tank with 4 mollies, 4 white skirt painted tetras, 3
catfish, and 1 pleco.  All of the fish seem to be getting along fine with the
environment except the tetras.  During the day when the light bulb is on they
hide underneath my fake rock which makes a shadow.  When the timer of the light
clicks off they will come out immediately and swim around.  I have experimented
and turn the light on and off manually and as soon as I turn the light bulb back
on they dart under into the shadow.  Why are my tetras so sensitive to the
light?

PS- I do not have any live plants.

Answer
I've never heard of Tetras being sensitive to light. I'm wondering if maybe they feel safer in the dark. Do you notice any of the other fish picking on the Tetras? How long have you had the Tetras? Perhaps they just need time to adjust. I don't think you need to worry unless they start acting sick, maybe getting a bulb thats not so bright would help.

I actually just thought of something.I used to have Tetras when I was a little girl and I remember reading that they are gentle natured fish that need large schools to feel confident. Maybe you should invest in a few more Tetras and see what happens.