White things on rock

[Sfplaya1]

 

[Crabs McJones]

Pineapple sponges possibly

 

[saltyfilmfolks]

Does look like sponges.

 

[Big G]

+1 sponges. Harmless filter feeders. Their population will increase and decrease depending on your tank conditions. They usually like to hang out in shady locations: under cliffs, sumps, overflows, etc.

 

[Sfplaya1]

+1 sponges. Harmless filter feeders. Their population will increase and decrease depending on your tank conditions. They usually like to hang out in shady locations: under cliffs, sumps, overflows, etc.

Are they a sign of a healthy tank?

 

[Crabs McJones]

Are they a sign of a healthy tank?

Absolutely!

 

[Sfplaya1]

+1 sponges. Harmless filter feeders. Their population will increase and decrease depending on your tank conditions. They usually like to hang out in shady locations: unde

 

[Tyler_Fishman]

They form intricate “root” systems where you’ll find filimentous structures on rock so it may look a little different than the main pineapple structure you usually see

 

[Big G]

They form intricate “root” systems where you’ll find filimentous structures on rock so it may look a little different than the main pineapple structure you usually see

Yes, sometimes they look like little white trees with bare branches.