Yeah for sure! They’re 100% fish and reef safe. And it’s actually good for corals too. Just make sure to keep a close eye on the Ph because melafix will lower it slightly. Personally, I mix a little ph buffer in cup before hand so I can add it with melafix just in case.
Also, you can use use the regular freshwater melafix too. A lot of places don’t sell sell marine products but you can get away with this. They’re the exact same thing the only difference is the strength. The freshwater is milder than the marine.