Plant Identification

[chessapeke]

I just started setting up a saltwater tank, thus far I have the water and live rock, still waiting for the nitrates and ammonia to zero out. Was checking stuff out today and I noticed a couple plants growing, was wondering if anybody knew what kind they were (see pic). There was also another one but I couldn't get a picture of it, the one I don't have a picture of kinda looks like a broom. It has a long stem and then about 5 or 6 little hairs spread out in a fan shape, its only about 1/4 inch tall, I'd like to know what that one is called if anybody has any ideas. Thanks.

 

[bang guy]

It's an algae called Caulerpa. It will need to grow out a bit more before I can give a positive id. Perhaps C. toxicology or C. Mexicanis.

 

[saxman]

The sprigs you have in the photo are likely Caulerpa racemosa (AKA green grape Caulerpa) or one of its variants. It's fast-growing...as in REALLY fast growing, and is actually classified as an illegal noxious weed in many states as they tend to take over their area. It's great for nutrient export as it will keep your NH3 and NO3 levels in check between water changes. It also harbors pods and looks nice.
Your other macro sounds like it MIGHT be C. taxifolia (AKA feather Caulerpa) or one of its variants, which is also considered a noxious weed. Threat it pretty much the same as C. racemosa.
The fast-growing Caulerpa species can "smother" themselves and go sexual (release gametes into the water) in a last-ditch effort to save themselves from dying. What you need to do is to keep them pruned back and thinned out (just yank the stuff out, and be sure to freeze any prunings for 24 hrs before tossing them).
You can tell when Caulerpa is about to "blow" because it goes milky-white with green spots (the green spots are the gametes). If you see this, simply pull out the offending pieces. Don't mistake white active growth on the tips for this condition.
Finally, if you have a reef tank, you'll want to get rid of the stuff as it can overgrow your corals. We use live macro in all of our FO setups, however, and the results are really great.
Here's a good ID guide for Caulerpa sp.
http://www.usc.edu/org/seagrant/caulerpa/SpeciesKey/index.html
HTH