ID please

[WaterWorld]

Can someone please tell me what these are? They are all over my glass, are they harmful?

 

[moorjames]

looks like Asterina

 

[ISpeakForTheSeas]

Can someone please tell me what these are? They are all over my glass, are they harmful?

Hydroids in their medusa stage - they're common in newer tanks and typically go away on their own.

 

[dedragon]

yep hydroids, not asterinas

 

[mike550]

Hydroids in their medusa stage - they're common in newer tanks and typically go away on their own.

How do they go away on their own?

 

[ISpeakForTheSeas]

How do they go away on their own?

Typically by starving - they generally feed on things like copepods, rotifers, Artemia nauplii, fish larvae/eggs, etc. which usually aren't present in large enough quantities to support the hydroid medusae in a new(er) tank that isn't purposefully adding pods to the tank.

 

[AydenLincoln]

Definitely hydroids that should die off as the tank matures!