This is just my experience so please don't take it for fact but I've had really good luck treating ich and possibly velvet with hydrogen peroxide.. I had Fairy Wrasse develop what I think was velvet but may have been something else along with ich and die very quickly in my tank. It was a new addition that I didn't quarantine. Soon after it died I noticed ich on my 2-3 inch hippo tang and what looked like the start of velvet on my 4 inch swallowtail angel.. I don't have a hospital tank and I really didn't want to set one up and after reading a lot of posts about treating with peroxide I decided to give it a shot.. I started dosing 1ml per 10 gallons of tank water daily at no specific time in the day and did this for a month straight with no issues on my coral or inverts and all my fish are still alive and looking good. I have no sps in this tank but I have softies, lps, zoas, gorgonian, bubble tip anemones, a tiny snowflake eel, various snails, an orange serpent star, and a macro algae reactor with a lot of chaeto, nobody had any issues and it didn't affect the chaeto at all.. Also I had some little patches of cyano that cleared up as an added bonus.. Durning this time I kept up with the weekly water changes and ran carbon and rowaphos as usual. I didn't change anything else.
Sent from my Nexus 6P using Tapatalk