brs fiji dry rock question

[easternreefer]

so I purchased some Fiji dry rock from BRS. had it stored for about three months. placed it in my new tank and lo and behold it appears that a sponge that was on the rock had rejuvenated itself and now has a siphon and appears to be growing? Is this possible? I am quite amazed.

 

[Maritimer]

It's probably a skeleton, from when that rock was in the ocean. It'll rot, and that rotting will produce some amount of ammonia, which will feed the bacteria you tossed in there, and your tank will cycle.

Sponges do remarkably poorly in air - it's one of the things that tends to kill them outright. Run them through a blender, they'll be OK, they'll put themselves back together - so long as you don't take them out of the water to do it.

~Bruce