Starfish/Snowflake critter

SuthernReefer · May 31, 2023

Ive got a small 10 gallon tank that I'm using for pods and macro algae. I just noticed these critters on the glass. Nothing has been in this tank except pods and pompom Macroalgae from Algaebarn.

Ive found images on the web, but can't really find anything that identifies what they are or if they are harmful. I'm worried that if they came in with the pods or Macroalgae, they are also in my 75 DP tank and I just haven't noticed them yet. It's taken 2 weeks for these to show up in the 10 gallon.

Ive seen them labeled as jellyfish hydroids, but not sure if that is accurate. This is them with a macro lens. Their limbs move. Can anyone tell me more about these guys? Everything ive found gives me a security warning or older threads where people ar

en't sure.

Thanks in advance

ISpeakForTheSeas · May 31, 2023

They're most likely a hydroid (a Hydrozoan) species in the medusa stage (as opposed to a true jellyfish, which is a Scyphozoan) - to get a genus/species level ID would require much closer up, clearer pics. That said, some medusae that look similar can be found in the Cladonematidae family, such as Cladonema spp. and Staurocladia spp.

Whether they're harmful or not may depend on the species (same with whether they'll disappear on their own or not), but the general consensus with hydroids is that they're either neutral or harmful.