Curious what these are??

[Zacharoo]

I had an ick outbreak which killed all my fish. My tank has been empty for around a month and these started popping up on back glass. Any idea what these are?

 

[Uncle99]

A Nudibranch?
If so, some good, some bad, most bad, can be very destructive to specific corals.
Berghia eat Aptasia.

 

[Reefing102]

Definitely looks like some type of nudibranch. Had any issues with corals getting ate or dying?

 

[Zacharoo]

I bought the tank with a hammer coral. Didn’t last long after the tank was moved from house to house. Can’t say for sure what killed it.

 

[Uncle99]

The prob may be not the adults, but the eggs or juveniles.
Unless your 100% sure it’s safe, remove.
Maybe a wrasse, or long nose hawkfish, might snack on the smaller fry and eggs.

 

[Zacharoo]

They don’t move around. They are attached at the base.

 

[LisaP]

Looks like a Sycon sponge (aka Pineapple sponge).

 

[Reefing102]

Looks like a Sycon sponge (aka Pineapple sponge).

Now that I’m looking closer, and with the not moving around, I would have to agree. I missed the details at the top of them. Harmless filter feeders

 

[Zacharoo]

Now that I’m looking closer, and with the not moving around, I would have to agree. I missed the details at the top of them. Harmless filter feeders

Thanks!

 

[Uncle99]

Got me too!