Yesterday we bought two goldfish to add to our collection. One of them is a Lionhead Goldfish (1 1/2 in. long) and the other, a Celestial Eye Goldfish (2 in. long) They both looked perfectly fine in the tank at Petco (I know, Petco isn't considered ideal) but the Celestial Eye did seem to linger more towards to bottom. Nevertheless, they looked happy and healthy. Same attitudes when they were in the bag on the way home. We have a 10 gallon QT tank set up and has been cycled for 6 months. Parameters before we put them in: Ammonia: 0 Nitrites: 0 Nitrates: 5. As SOON as we put them in, the Celestial Eye dropped to the bottom. Breathing normally, but laying on the bottom. Thought maybe it was stress. 30 minutes later, she is still on the bottom. Occasionally gets up and twitches around now. But still breathing normally. Sometimes she even gets up and pecks at the rocks, but stays very low, and will not accept food. So, as the night comes, we turn the lights off. She gets up, swims around, still close to the bottom, but exactly the way she was at Petco. Happy and healthy! Pecks at the rocks, finds the food from earlier. But still every 5 minutes or so, she takes a break it seems, and lays on the bottom, still breathing normally. The Lionhead is always checking on her too. Idk guys. What could this be? Have I done anything wrong? Do these Celestial Eye Goldfish require some sort of special care I am unaware of? I'll include pics of when the lights are on (3) and off (3).