What is?

[Jblaine]

Just noticed this growing on the rocks in a QT tank that I am observing some new fish. Can anyone tell me what this is? The rock is out of my sump in my DT.
Thanks
Jon

 

[ying yang]

My guess would be sponges and possibly some hydroids.
I take it your sump is in the dark ? Most sponges like dark or shaded areas.
The hydroids the little flower looking things or what to me look like flowers.

But let's see what others say

 

[Jblaine]

My guess would be sponges and possibly some hydroids.
I take it your sump is in the dark ? Most sponges like dark or shaded areas.
The hydroids the little flower looking things or what to me look like flowers.

But let's see what others say

Yes sump area is dark. Are these bad or is it ok?
Thanks

 

[ying yang]

Well only bad thing I read others say about sponges,is some can choke out corals,one guy on here says he got lots of a blue sponge that releases toxins if he cuts to much back at once and kills some his sps.

As for hydroids ( if that's what they even are) they can sting nearby corals