Identification help.

[dnd091303]

These just appeared on a piece of live rock that has been in my tank for at least 5 months. I have no idea what they are please help with identification.
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[k3nnyp]

Sponges. Harmless filter feeders. I have them in my tank.

 

[ringo®]

Yeah, pineapple sponge.

 

[dnd091303]

Thanks guys. With them popping up like they did, does that mean my tank is healthy. That rock has been in the tank for about five months, plus I have a couple more on the cords of my hydro pumps.

 

[jennm]

I'd say it indicates a healthy system. They are tiny filter feeders so they help with water quality as well - well as much as a tiny critter can.

Angels will eat them, but they aren't a nuisance as such, unless they replicate in unsightly numbers - I've seen that a time or two, but that is rare. They won't harm anything.

Jenn