we just got our first fish tank last week and our fish (tetras) hide in the plants(fake) and dont move when the light is on. they dont even like to move around to eat when the light is on. as soon as we turn the light off, they become very active and use all parts of the tank. is this normal? we have a 10 gallon tank with a 15w 8000k t8 full spectrum light that came with the tank. should we get a different bulb or more plants? any help would be appriciated.