i am told i have dragons plague on some live rock in my salt water aquarium, what is this and what should i do

Question

it is like a red moss

Answer 1

I've been keeping saltwater tank for 8 years and have never come across this name before (this is the problem with a common name - everyone has a different name in different areas)! I'm going to take a guess that this is some type of macroalgae and go from there.

First, let's make sure it isn't red cyanobacteria: http://wetwebmedia.com/Algae%20and%20Plt%20Pix/BlueGreenAlgae/BGA_RedAQ.jpg, http://www.unep-wcmc.org/marine/coraldis/cd/I/rbd%20II%20steph.jpg This is usually in flat sheets or on the glass, but can grow into 3D shapes.

From your description this sounds like it might be a gracilaria, or agar algae, in which case this is a good fish food (if you have omnivores/herbivores). You might check the photos on the site below and look up the name of the group:
http://saltaquarium.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fvis-pc.plantbio.ohiou.edu%2Falgaeimage%2Fimageindex.htm, http://www.lareefs.com/index.php?main_page=index&cPath=1&zenid=eb8b8da85350e69703a749077df27bf0, http://saltcorner.com/sections/guest/algaepage/algaepage.htm

If none of these looks like what you have, could you maybe post a photo?

Some algae control links:
http://www.reefkeeping.com/issues/2007-01/sl/index.php
http://home2.pacific.net.ph/~sweetyummy42/algae.html