What could this be ?

[Luke2112]

Crustacean like things in my tank , could they harm my tank , some are dead some are alive

 

[AbsoluteFaye]

Those are pods. Beneficial to the tank and people pay money for those! Certain fish eat them like dragonetts.

 

[obscurereef]

Yay, amphipods. There's a type that eats zoas, but those aren't very common. They're very large in size. Wouldn't worry about it though.

 

[Luke2112]

Oh great thanks alot guys