white spots on vlamingi tang

We have recently intoduced a show vlamingi tang to our 300g fish only tank. He has small white spots covering the whole fish.
Other fish in tank---naso, clown, foxface and purple tang, couple of groupers, couple of puffers, french angel, lion fish. The levels are fine, good protein skimmer, could this be stress????
ps he is eating and swimming around more.
 
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