 My Yellow Tang is letting this Wrasse nip at him...wtf?
So yesterday I bought this Fairy Wrasse 
I forgot what it is called. Does anyone know? I just happened upon this pic when I googled "Fairy Wrasse." The tag under the pic called it a Temmincki but when I googled that it came up with all kinds of stuff that look nothing like this guy.
Anyways the other thing I'm wondering about is his interaction with my Yellow Tang. Like the title said, it's as if the Tang is LETTING him nip at him. I've heard of fish cleaning other fish and stuff like that, so I think that's what's going on here.
The Tang...well...assumes the position  He faces down and fans his fins, then the Wrasse comes by and starts nipping at his under belly and sometimes his swimming fins. It doesn't seem like any damage is being done, and I would imagine if this was an attack then the Tang would retaliate instead of just putting up with it. Right? _________ 125 Gal Reef. Born March 2002 FISH: Ocellaris Clown, Yellow Tang, Fairy Wrasse, Sand Star, Fuzzy Dwarf Lion, Mandarin Dragonette, Hippo Tang CORALS: Green Striped/Red/Purple Mushrooms, Green Star Polyps, Yellow Toadstool Leather, Bubble, Frogspawn, 2 Hammers, Yellow Polyps, Open Brain, Ridge Leather, Various Zoas, Button Polyps, Kenya Tree, Colt, Elephant Ear Mushroom, Clove Polyps, Torch, Purple Clam, Rose BTA | 
