Greenish Blue Tubes on Live Rock

Question
I've had a 95 gal saltwater tank up and running for 6 weeks now, and have a large number of these green/blue tubes popping up on my live rock. They are no wider than the tip of a pen and maybe an inch tall on the biggest ones. Some of them "curl" up a little...it also looks like it has many segments that make up the tube. What are these things?

Answer
Hi Derrik. From your description it sounds like you have a form of hair algae from either the species Chaetomorpha, Cladophora or Enteromorpha. Usually these three forms of algae are very easy to control. They are palatable to many fish and invertebrates and easily removed by hand. They bloom in new reef aquariums with a high phosphate level due to decomposition from fully uncured liverock. The one species(Chaetomorpha) is used often in refugium filters to help control nutrient levels. For control, Check your phosphate level and correct it if needed using phosphate absorbing material. Removal by hand is sometimes enough to keep this in check. You don't have to remove it if you don't want to. It is usually not very fast growing and can be beneficial if kept from getting out of control and growing over corals and things like them.