Unknown Macroalgae Driving Me Crazy (Photos)

[joeychitwood]

I've search several algae databases and image galleries, but I cannot ID this specimen. No one in the Reef Discussion forum seems to know what it is either. The macroalgae is now growing in three areas in my 55 corner tank. It is extremely tough and does not come off the rock when brushed with a stainless steel brush.

It is dark green, with areas that appear brown and even black. None of my fish or crabs will eat the stuff. Can anyone out there ID this algae?

http://images.mdlindquist.com/unknown%20algae%20005%20%28Large%29.jpg

http://images.mdlindquist.com/unknown%20algae%20012%20%28Large%29.jpg

[joeychitwood]

A bump in hopes that someone knows what this is.

[TAMike97]

It looks like Brown Gracilaria. I am no expert though.

[piercho]

Pretty sure its in the red algae family. Maybe an idea on genus. When you pull it apart, what is the texture like. For instance, is it strong and feels like pulling apart thread? Also, remove some and try to get a macro mode picture, using flash, if possible. Thanks.

[piercho]

Duhh... I should take the time to read...It is extremely tough and does not come off the rock when brushed with a stainless steel brush. Search on gelidium - aka "red wire algae". IME Diadema urchin will graze it preferentially. The little tuxedo urchins not so well, IME. Generally a palatable algae, and robust grazers like Siganus (rabbitfish) may take it on. Not sure on the ID so I would seek additional inputs.

[djperezo]

Its hard to say it could be either Gracilaria tikvahiae, or some gelidium sp. but either way, its a nasty nuissance algae