Help with Pectoral Fin

[Peterski]

I have a Marine Betta, just purchased a week ago. Has some sort of fuzzy looking thing on one of it pectoral fins

Infected fin

Non infected fin

Current biocube setup with two clowns and wrasse. No signs of aggression

 

[EmdeReef]

Not easy to see in pics. Does it look like this?

https://www.reef2reef.com/threads/lymphocystis.257461/

 

[Peterski]

Not easy to see in pics. Does it look like this?

https://www.reef2reef.com/threads/lymphocystis.257461/

It’s under the pectoral fin. I have to try to get a better pic, new fish hiding.

Description sounds like it, but it’s only on one fin so far.