Foxface for hair algae with black back bfly?

[Dearth]

Unfortunately most species of fish/inverts will not eat thick mats or heavy concentration of hair algae but they will eat small areas of infestation and do quite well with containing and controlling it.

Sea Hares are as far as I know the only one that will gleefully attack hair algae as it is the only thing it eats.

Best bet is manual removal