Found this with some recently purchased live rock.

[yourmom]

 

[PicassoClown04]

Hi! It appears to be a single polyp of a zoanthid. If you can get a pic or two under some blue light I can try to ID it for you!

 

[Dolelo96]

Looks like a majano anemone

Salty Underground: Majano Anemone Control

The chemical I used to remove the Majano anemones was calcium hydroxide. It is commonly referred to as Kalk wasser, Kalk, and Pickling Lime.

saltyunderground.com

 

[RVA REEF]

not a zoa looks like anemone

 

[yourmom]

Hard to get a good photo. It is about the size of a green pea. There was another one in there even smaller. Safe to add? Definitely alive.

 

[Cell]

Looks like a majano. I'd probably toss it.

 

[reefd00d]

I'd guess Mojano too. Out it goes! Don't want those!
What's the small red thing at the top of the photo? Rubble or flatworm?

 

[yourmom]

I'd guess Mojano too. Out it goes! Don't want those!
What's the small red thing at the top of the photo? Rubble or flatworm?

I think rubble, or coral bone. I scooped it up to see if it did anything. These guys spent the last 20 hours in a cooler with some rocks. I am setting up a 20 for my office from scratch and wasn’t planning to add much, if any, coral. I don’t have a good light yet. My 40 in the living room is still cycling. I am wondering if they would be fine in my 20 as the only addition beyond fish or maybe some mushrooms?

 

[reefd00d]

I think rubble, or coral bone. I scooped it up to see if it did anything. These guys spent the last 20 hours in a cooler with some rocks. I am setting up a 20 for my office from scratch and wasn’t planning to add much, if any, coral. I don’t have a good light yet. My 40 in the living room is still cycling. I am wondering if they would be fine in my 20 as the only addition beyond fish or maybe some mushrooms?

Not sure what you are asking about what would be fine in the 20g? I would not put Mojano Anemones in my tank. They are considered a pest. But it's your tank. So just google it and make your decision.

 

[Cell]

They tend to multiply fast and will eventually overtake your mushrooms. But otherwise, go for it. I kept a pest tank for a minute.

 

[yourmom]

They tend to multiply fast and will eventually overtake your mushrooms. But otherwise, go for it. I kept a pest tank for a minute.

Any problems for the fish? I have a pajama Cardinal and cleaner shrimp, haven’t added anything else. I think it’s kind of pretty! If it gets out of hand, would I have to throw out all of the rock or can I remove them?

I hadn’t planned on keeping corals in my 20 long that I’m starting in my office. I’m going to throw this thing in early and see if it makes it, I might keep a pest tank as some have described! Then I can maintain a nice, controlled reef tank in my main tank and throw the random guys in my office and see what happens. I kind of like the idea of experimenting in there and if these only pose a threat to corals or because they grow quickly they could be a good cheap option for in there!