New! Need help with live rock

[g_iako]

Hi! My husband and I just started our first saltwater tank not too long ago. We have some live rock and two clown fish. We had two hermit crabs and a snail, but one of our crabs gave our tank ICK. We treated the tank with some kind of drops, I'm not sure what it was called, my husband received it from the saltwater aquarium store that is local to us, and the crabs and snail died. Our two fish are fine, but now we have these things growing on just one of our live rocks. I've been looking around online and haven't been able to figure out exactly what it is, so I was hoping someone from here would be able to help, Thanks!

I tried to get the best picture I could, they are small white things that are sticking up off the rock and seem to have two antennas or whiskers of some sort.

 

[Sk8r]

Those are sponges, I think, and you came perilously close to crashing your tank and having to start over. The sponges are actually a good sign you didn't kill your rock.
NEVER treat your whole tank. Ever. I suspect what your lfs gave you was tea tree oil, but not sure. If it had been copper, you'd have a dead tank.
There's a sticky with a red arrow up top. REad that as thoroughly as you can.
THe fix for what's been done so far is a product called PolyFilter. Get some of that and put it into your water flow for about a month or until it turns brown. That should remove whatever went in that killed the invertebrates. Crabs, for the record, don't get ich. He may have had a spionid worm on his shell. They make little round white bumps of calcium carbonate.
YOu've dodged a bullet. Once you've cleaned up the treatment you can get more snails and crabs. You also need a quarantine tank, which can be a simple filtered glass box, no sand, no rock, just a filter, and heater, no light, but you may need a jump screen. Put any new fish or critter into that for observation for 4 weeks before putting them in---the sticky above will explain that, and explain about water testing and other needful things.

Hope that will get everything on even keel. [welcome]

 

[Fishmas]

They kind of look like plankton from spongebob. If you killed the invertebrates you may have used copper solution of some kind. You may want to have aggressive water change cycle for a few months. Maybe go to water chemistry thread and ask ?

 

[TimeConsumer]

Looks like plain old pineapple sponges to me, and one aiptasia.

Piece of advice: Don't panic. This hobby is full of surprises. Take your time to determine a proper course of action for situations.

 

[g_iako]

thank you for all your advice! My husband used Parashield by Mardel, turns out my snail was alive, just stuck upside down, poor guy. But I think I might have spionid worm's? I have small white circles on the back glass of my tank and only on this one rock, sounds like what you described above, are they harmful to my tank? I only see the white dots, no worms of any sort, not sure if I would be able to see them anyways, again thanks for all your help!