Algae will not be eaten by tangs or clean up crew

[benscorals]

I have 50 urchins, 50 Trocus snails, 200 blue legs and 20 tangs and nothing is eating this algae.

 

[sixty_reefer]

If nothing is touching it there is a chance that what you have is Chloridesmis sp. Very similar to common GHA with the main difference being that it contains a toxin that keeps herbivores away.
I’m not aware of any natural methods to eradicate this species.

 

[Dan_P]

I have 50 urchins, 50 Trocus snails, 200 blue legs and 20 tangs and nothing is eating this algae.

Photo of algae under white light please.

Such a large CUC is likely to starve, no?