Its not invasive. Its really cool. If you get enough of it growing you can keep a seahare too. I've kept the Caribbean Spotted Seahare (Aplysia dactylomela) with the Red Grac. They love it! You have to have a lot though because they eat a ton of it each day.
I put it in my sump with my cheato. Is it ok in there? and what is it good for other than seahares?
wow you had red gracilaria dom? Got any left?