What's is this

[Auto-pilot]

Hey I don't know what these are, they are attached to my Acan frag I got a while ago. At least one has spread to a rock in my tank, should I get rid of them, do they sting corals?

 

[Sashaka]

If you're talking about the little white spots on the rock, they're calcareous worms. They are not dangerous, just annoying because they multiply and stick firmly to the glass of the tank and have to be scraped off.
If you're talking about the purple flower like creatures surrounding the coral, I'm not sure. At first I thought it looked like nudibranches but on closer inspection it looks like separate animals with separate mouths. It's hard to tell, but if you think they're nudibranches, get them out of the tank quick. I tried to count what looks like 'petals' on the creatures to help Id, but I could not get a firm number. It sort of looks like Alveopora Sp., but the way it's growing around the other coral doesn't seem right for flowerpot coral. Maybe someone else has seen this before.

 

[reef lover]

Tunicates.

 

[Sashaka]

Tunicates.

Wow, really! I always thought the common feature between all tunicates was an oral siphon (water intake) and the anal siphon (waste outtake). I can't see that in the pic. If this is a tunicate species that multiplies well in our aquariums, @Auto-pilot might have a coral he can propagate and sell in the R2R market place! I've always wanted to keep tunicates, especially the blue lollipop kind, but I know they are generally quite delicate and don't last long in many home aquariums.

 

[reef lover]

They come in all shapes sizes and colors. These are close...

 

[Sashaka]

They come in all shapes sizes and colors. These are close...

How awesome! I'll be researching more about this species today. Thanks!

I see they are an invasive species in the wild.

 

[Auto-pilot]

I feed photo on the regular and that's probably why they are doing so good. You can have them lol

 

[AeldariDrukhari]

My buddy gave me his tank and corals recently and I see this hitchhiker all over the rocks and in between the zoa's. Glad to see it's some sort of tunicate.

 

[Auto-pilot]

Mine eventually died off!