What in the world is this alien looking thing?!!!

[Zagecko]

Every now and then I look at my glass closely and notice copepods and sometimes these. And I am not sure what these are or if they're good or bad.

 

[j.falk]

hydroid jellyfish

 

[vetteguy53081]

Hydroids and hydroids should be removed manually with edge of a credit card into a net and discarded. They WILL sting corals that they come into contact with, so cutting down feedings will often help get rid of them. They favor brine shrimp as a meal.

 

[Zagecko]

hydroid jellyfish

Wow