What's This Macroalgae

This algae started growing out of my chaeto; any ideas on what it is?

 

it is invasive and ... i hope you have it in a sump not in your tank !!!!

 

budsbunny, thanks for the reply. Unfortunately it is in my tank, but I am working on removing it.

 

The macro in question appears to be Caulerpa racemosa, var. peltata (AKA suction cup Caulerpa).

As mentioned, C. racemosa is one of the species that is considered a noxious weed due to its invasive growth rates. We've used it in DT's, but you do need to keep it pruned back. It's also one of the species that is more likely to go sexual, along with C. taxifolia.

 

+1 This is actually a safe plant to keep except as stated above it grows fast, uses small amounts of calcium, and grows runners which attach to the rock and can be a real pain in the ass. On the plus side it is very fast growing and is a great great great great plant for reducing nitrates. Much better than chaeto because of the fact it grows so fast. I have some in my refugium and when its time to prune I literally take out 90% and it still grows back and becomes larger than my chaeto ball.