Reef safe doesn't only mean safe with coral. It also implies that a creature is safe with invertebrates and other fish as well. Harlequin Tusks aren't considered reef safe because they are known to eat inverts, like shrimp and crabs, and some times small fish too.
I have had a couple tuska, and have a juvi now. They will eat shriimp, crabs and snails. Ofcourse smaller fish too. IME they are fish friendly with most. the larger tusk i had did not like my dragon wrasse and would chase it on end. I set the tank differntly, I brought the middle of the rocks out towards the front glass. hence kinda dividing the tank. Kinda giving a blind so when one fish turned the corner it didnt see or be seen by the other.
I also was able to hand feed the tusk silver sides. IMO it is a very nice reef fish and a good tank mate.
* provided the tankmates arent small enough to be eaten, they will. And they need room to swim. They are open water fish that swim a lot :wink:
