Tag alongside in my chaeto

[tigerlili]

I have been so careful in starting my new reef aquarium and I made the mistake of adding store bought chaeto. Currently i am still cycling my tank. (~120g on week4). I already killed some flatworms. But now I see a crustacean looking thing? Is it good or bad to have? Help!!

 

[Vette67]

amphipod. Good guy. Sign of a healthy tank.