Just out of curiosity... how old is he?
The reason I ask is that I was given a 7 year old velvet damsel earlier in the year . He did not deal with the stress of being caught and transferred and behaved the same way that you are describing. After discussing the condition with two trusted LFS
, one suggested that he had had a stroke type event and that she had seen this before in older fish. The other LFS
said that she had seen this happen in fresh water fish, but had never seen it in salt. I don't know if strokes are even possible in fish, but found it an intersting thought.
I ultimately had to euthanize him as his constant twirling on his tail was causing large wounds.