Mandarin, should I be concerned?

[SteveMM62Reef]

I have a Mandarin that’s been in my Aquarium for a little over three weeks. Traded from another hobbyist for some Corals. It was fully quarantined, but was skinny, but has fatten up in my 120 gallon. In a couple of mornings I noticed a slimy thread coming off its top fin. Didn’t see it last night. Today there are white spots just at the fin. Is this sand stuck to the fish mucus layer?

 

[jthunderzzz]

Mandarin's do have a thick slimy coat as a defense. I have seen this on mine before and he is still doing great. They are pretty resistant to diseases so I wouldnt worry too much. Biggest challenge is them eating lol

 

[OrionN]

Mandarin secreted a lot of mucus at night. When first get up these mucus still on him and has sand sticking on to it. No problem. Come off after he is up and swimming around a bit. No worry.