What is this "red beard" stuff?

[tarponchik]

Akumal reefs, found mostly on sea fans and alike. Clogs are 3-5" across but some are up to 6-8".

 

[scubafanatic]

Reminds me of the invasive red growth the Martians brought to earth in the movie 'War of the Worlds' (with Tom Cruise)

 

[archman]

It is a rhodophyte of some kind. Best guess is a Gracilaria, given the strand size you're describing.

 

[tarponchik]

It is a rhodophyte of some kind. Best guess is a Gracilaria, given the strand size you're describing.

Thanks! So this is red algae? Wiki says "Gracilaria commonly appears as a macroalgae for sale in the aquarium trade. It is a highly palatable algae to tangs[6] and many other herbivorous fish..." Strangely, I haven't seen any fish eating it.

 

[archman]

Perhaps that wiki entry should substitute "highly palatable" with "reasonably digestible".