What is this? (and not one!)

[kobibm13]

They have been growing for a while now and I noticed their quantities are getting bigger and bigger. What is this and what should I do?

 

[AllSignsPointToFish]

They look like bristleworms. They eat detritus. You can remove them if you want, but they are typically harmless.

 

[twilliard]

bristle worms. They are scavengers
Some keep them and some do not.

 

[kobibm13]

Thanks! I'll keep them for now

Any chance they eat the brine shrimp young I had living in these rocks?

 

[v10king]

They have been growing for a while now and I noticed their quantities are getting bigger and bigger. What is this and what should I do?

Bristleworms, and lots of them. These are good for your tank, I Would leave them to breed!

 

[Tahoe61]

Based on the amount of Bristleworms I see I would be inclined to think you're over feeding.

 

[wattson]

I would honestly get rid of your crushed aragonite gravel,,,it is a detrius trap and nitrate holding monster of a problem..
you see why you have SSSOOOOOO many bristle worms in it..too much waste collecting in it now,,hence why you see so many bristle worms..
take it out and put coarse sand or go bare bottom,,but take the gravel out in steps..not all at once..plenty threads here to help you out on how to remove old sand and crushed aragonite..