Oh no - problem with our fav Yellow Leather Coral

[Pansy-Paws]

Hope someone can tell us what is happening. These yellow lines first started appearing 3 days ago. Today, there are some spots along the yellow lines where the coral flesh is gone - like a small sore. We've had this coral for 2 years and really hope you experts can give us some idea of what's happening and what we can do about it. Thanks.