Need ID

[Khaw]

Found these green things on new bought mushroom rock. What can it be?

[Khaw]

Found these green things on new bought mushroom rock. What can it be?

Picture below

[ryz]

Halimeda spp. Calcareous Algae

[Gouldian]

Yup, I believe they are halimeda too. They are a good indicators of KH & Ca, if both are sufficient you can see they multiplying.

But same as Coralines, some people dun like them claiming that they adsorb too much Ca.

I am looking for them actually if you dun want can frag it for me?

[Khaw]

Thanks. As first I also suspect the things to be algae, but I observed that the size of them shrink at night and expand under light. Expecially the luminous green portion get smaller and white edger increase after light off. Look like they are contracting. Will algae behave this way?

[ryz]

it is a type of algae...

even leaves of trees become flaccid and droop in the night and become erect and outstretched in the day... so why not algae?

Do a search on halimeda algae if u need more info

[Khaw]

Has done a search on halimeda algae in the web. Did saw somethings similar on my old live rock, but don't look like these greenish things. Maybe it still at the early state of algae growing. There shape are just like ruby and the color are so luminous. I think the only way to confirm is to let it grow larger and see. Hope it can survive in my tank till then.