i have just recently bought a new 10 gallon tank(let it cycle) and then 5 days ago i bought 1 female betta and 3 tetras the betta has just started to eat but all she does is sit behind the filter and hides whenever i enter the room. its really strange at night time her fins will be red and in the morning they will be blue but during the day they are yellow and she is gray i was wondering if this is normal for a new tank and a new fish??