What are these plants or living things??

[dhutchinson81]

I have reddish brown plant like things in my 75 gal salt water aquarium. They have multiplied and I now have about 100. They have a tube like bases and spikey tentacle like tops - see picture. I just recently realized that they take in food much like an anemone. Can someone please tell me what they are?

 

[aquandrew]

those are aiptasia, a pest anemone. if you ever plan to add coral, you will need to extinguish them all

 

[Mebbid]

Wow, that's a lot of them. There are various removal methods, Aiptasia X, Kalk paste, lemon juice, or whatever. I would also look into getting a few peppermint shrimp as well. They will help control them after you manage to kill most of them. Just be sure not to physically remove them because any tiny bits or pieces that come off will just grow whole new ones.

 

[dhutchinson81]

But what are they and are they harmful?

Thanks!

 

[Mebbid]

They are a pest anemone and yes they can be harmful, especially to corals.