what is this plant called?

[erkil]

Got this little green plant growing on my rock and , a white plant that looks a coral or something can anyone tell me what they are?:hi1:

[Rodgec1]

Not very clear pictures but I am sure someone might have an idea.

[jeff_k]

1) cyanobacteria/halimeda (http://reefkeeping.com/issues/2004-04/nftt/index.php)
2) coral skeleton
3) coral skeleton

[ShipWreck]

The Green looks like halmedia (sp?) a calcium based plant. Can be hard to eradicate if you let it take a strong foothold. A small piece of it can make an attractive addition.

The white thing looks like either a dying coral, if this is fresh rock, or some type of sponge. If it is in a shaded or dark area I would say sponge.

[MomentsofSanity]

Agree the first looks like halimeda and that the others look like sponges.

For the halimeda if you manually remove it make sure to get the anchor out of the rock as well. It is very slow growing so it won't take over like other algaes. Check your magnesium levels as people have had success keeping it at bay by elevating their mag levels to around 1500.