I've just started my 50 gallon tank. On the third day I put in 5 Giant Danios and they were doing exactly what I thought they should, actively swimming around. The next day, they all seemed to be hiding in the rear of the tank behind some cover. I'm not sure if they are scared of the light as I interact with my fish when it is dark in the morning and I need to turn the light on or at night when I get home and same thing I turn the light on. The only thing is when I turn on the light at night it stays on until about 10 and they still don't seem to come out of there shell. Any thoughts? My tank is still cycling, PH 7.0±, Ammonia-trace readings, Nitrites-low readings, one reading above 0, Nitrates trace readings.