Tons of aiptasia?

[vatizdiz]

Hi new here.
Are these aiptasia?
They are growing inside barnacles getting almost no light.
The trochus snails are babies about 1/4 inch big for size reference.

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

Those are hydroids - similarly to Aiptasia, removal is generally recommended.

 

[liddojunior]

Welcome to Reef2Reef!

Those are hydroids - similarly to Aiptasia, removal is generally recommended.

They also kinda just go away on their own with time. I don’t think they can finish the life cycle in aquariums

 

[ISpeakForTheSeas]

They also kinda just go away on their own with time. I don’t think they can finish the life cycle in aquariums

It depends on the species (possibly including if they're photosynthetic or not) and aquarium - some go away on their own, some can become invasive.