Its a dip with peroxide. Peroxide treatments are being discussed on the humble.fish forum. See below for the link to the hybrid tank transfer method I used on my eel and puffer when they had velvet. It worked out well.What is peroxide treatment? Similar to freshwater dip? Also what fish are copper sensitive...he heard rumors but not seen a specific list in a long while.
Hybrid TTM to treat more parasites!
Important - Tank Transfer Method is most effective when water temperature and salinity are kept within this range: Temp: 24C-28C / 76F-82F Salinity: 27ppt-35ppt / 1.020 SG - 1.026 SG "Hybrid" Tank Transfer Method (updated 2-9-2023) Tank Transfer Method is an effective (non-chemical) treatment...
humble.fish
Scale less fish such as Puffers and eels are easily affected by copper. I know there are also some wrasse species, but I dont remember which ones. I had my eel and puffer in copper initially and I could tell they did not like it. Once I got them out and started the hybrid tank transfer method they immediately looked better and were eating.