I have had 3 2" congo tetras in my 75 gallon planted tank for about 10 days now. I run a Coralife 260 (4x65) watt light fixture from 11am to 9pm every day. Every time the light comes on in the morning, the tetras go to the bottom back of the tank and hide. The plants are mostly in the back right now, so I assume they are hiding in the plants because they don't like the light. When the lights go off they come out and swim around like usual. My lfs has a 75 gallon planted tank with congo tetras and more light than me, but their fish swim in the front all the time. The only other fish I have right now are 2 bn plecos and a red glass barb. The barb swims around everywhere even when the light is on. I have 0 ammonia, 0 nitrites, and 30ppm nitrates. I do 50% pwc every week. Do I have anything to worry about? TIA.