Something is growing fast

[angus129]

When I left home this morning the live rock looks fine but when I came back at night I found some brown stuff growing on the rock. Can someone tell me what is it? Is it harmful for the fishes?

 

[little_fish]

That could be start of dynos, which is a pretty awful algae to have. Is it continuing to grow at record pace?

 

[angus129]

In the morning its tiny but when i came back it is already an awful chunk!!!How should I remove them?

 

[Northstar24]

I'd suck out as much as you can using a syphon hose. Try not to let it break up when you remove it, or it can spread around the tank. I'd also step up water changes

 

[angus129]

i tried to take out the live rock in hope to manually remove them, but as soon as I took it out of the water, everything retracted and nothing can be removed...