Bright Yellow on Live Rock


New member
Hello! I'm not sure if this topic is well suited for this thread, but I firgured it with worth a shot!

New to the forum, as well as reef tanks. I have a 14 gallon nano cube. It has been cycling with live rock for approximately 4 weeks. All levels are within normal limits.

No fish or any livestock yet. :fish1:

Over the past 2-3 days, a piece of live rock (which i purchased already purple), has been growing BRIGHT (neon) yellow. I've done some research on this forum, and past threads have mentioned it to be coralline algae, though I'm not entirely sure.

Any additional thoughts? Ill attach pictures.


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New member
I have some yellow sponge that grows on my rock, but its a little thicker and not neon.

In the sponge I can see little filter tubes coming out of it.


I have some yellow tube sponges that grow on my live rock. It looks pretty cool. I like it. Just some beneficial filter feeders.