Hi Christina. not sure if it would be a factor to take into consideration, but I did go a bit over the reccomend copper amount for my fish once because the velvet was so stubborn. This ended up effecting my Mccoskers flasher wrasse and Angel fish since they are more sensitive. They displayed symptoms of hyperventilating and hiding. If it was worse it was as if the wrasse was trying to spit something out his mouth. Moved him to another tank that was void of copper and he was fine later on. I think you should have plenty enough O2 being put in the water. Perhaps he is being effected by a pathogen. Generally in my experience a fish would not hide if it needs more oxygen, but it would gasp at the surface of the water. Whats he looking like now?
Hi Charles, thanks for the input! I was worried yesterday I'd gone over, but it was at 2.18 - I double tested it with Hanna. The wrasse had no reaction, which I'd expect since it's usually more sensitive than the tilefish, especially given the tilefish already went through copper before and was totally fine.
He's looking way better so far! I turned off the tank light earlier today to help calm him, and just left the room lamp on for ambient light, and so far so good. He's swimming at the front glass begging for attention and looking for food in the sand, the usual behavior. I still see him breathing a bit faster than normal, but it's a huge improvement from yesterday.
He seems pretty sensitive to light changes and sudden movements at night, so I'm being extra mindful. Fingers crossed it's only uphill from here - I love this fish so much already only after having him for a short time, and really want him healthy and happy.