Marine Velvet (Amyloodinium ocellatum) is arguably the nastiest disease for your saltwater fish to get. Marine Velvet kills most fish it comes into contact with and when you see Marine Velvet on a fish, it is very likely too late to treat the fish and save it. (A fish affected with Marine Velvet looks like it has been doused with powdered sugar. The fish will have very small white dots all over it.)

While you likely can’t save the fish that is affected with Velvet, you can treat the surviving fish, but not with hyposalinity.

Here’s why.

Marine Velvet looks at hyposalinity and laughs as it has been documented to survive in very low salinities- from 3 to 45 ppt (1.002 – 1.034 specific gravity) (Noga, 2000). Given that hyposalinity treatment for saltwater fish falls in the 11 – 16 ppt range, Marine Velvet will survive just fine in a hyposalinity environment.

Therefore rule hyposalinity out for marine velvet and use copper instead. Copper has been proven to work against marine velvet and I’ve found it to be very gentle on the fish if you use the right type which I’ll discuss tomorrow.