Hi, This is probably the silliest question but here goes. I have 6 very small tetra's (I am not sure about exact type I think 3 are black finned and 3 are really small kinda reddish with black markings) and 2 glass cats. My question is why do they swim around happy and playful only when I turn off the light in the aquarium? If the light is on the tetra's group together and hide behind a decoration I have in the tank and close to the bottom. the two glass cats hide together under the waterfall from my filter. They are very healthy, very happy, they eat good. I have a bio-wheel filter all the water levels are perfect (I test 3 times a week with API Master Test Kit). The only thing is with the light. What should I do as I know they need light for their health but they look so scared when it is on. I have googled this and checked everywhere but no one else seems to have the same problem. Am I just crazy. Sorry I forgot it is a 15 gallon tank.
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