What are these?

[Camd4k]

Found these guys on my glass what are they?

 

[SHNICI]

look like Hydroids to me, and most of the time if the tank is newer (say 1-3 months old) you can see this little rockets like pulsing around. also they can be the juvenile/larvas of some sort of life in. But I'll bet on hydroids jellyfish

 

[SHNICI]

Link - GOOGLE

 

[jfoahs04]

Hydroid jellyfish. Common in new tanks and generally go away over time

 

[Camd4k]

look like Hydroids to me, and most of the time if the tank is newer (say 1-3 months old) you can see this little rockets like pulsing around. also they can be the juvenile/larvas of some sort of life in. But I'll bet on hydroids jellyfish

Are they harmful?

 

[SHNICI]

Are they harmful?

yep, they'll disappear over the time usually. you can read here about them

 

[jfoahs04]

Not particularly. They can allegedly sting a little and some say your fish can feel them, but they aren’t going to kill or severely injure your fish or coral either. They’ll generally go away in their own over time. I still see one or two every now and then in my 3 mo. old tank.

 

[Ryan hirano]

Hydroid jellyfish. no worries there