so I’ve had a pair of regal angels in my system for a few years now they tend to get along. Recently, I noticed a smaller one swimming at the surface. This has been going on for a few days now, and it appeared to only be during the evening hours. sometimes the pair would swim up top as if doing a ritual. Today I woke up to the smaller one now, vertical and trying to eat off the glass braces out of the water. He is taking a turn for the worst. I have him in an isolation box. Please see video any thoughts of what might be going on. All other fish in the tank were good no change in medication no changes in parameters. I had a feeling that perhaps it was a snail that stung the fish while sleeping.