ID Please

[XxRyosukexX]

Hello I need an ID on three things

Is the bug harmless? And is the red algae a macroalgae, is it invasive?

 

[charlesr1958]

The "bug" is quite large and at first I thought of amphipods but it may also be a shrimp. The second one is a "feather duster" worm, a harmless planktivore/detrivore. The red algae is something I would get under control as any algae can be invasive. Might moving the rock to a refuge be your best chance as any small fragments left behind will simply grow again.

http://www.chucksaddiction.com/The Natural Reef Aquarium Part Three.html

Chuck