Little bugs HELP

[chubbyhubby]

Hi can anyone one help . I seem to have hundreds of these little bugs hiding in my blacked out over flow chamber. Plus this root looking stuff.

Any help would be great.

Also have alot of these seems more every day.
Thanks for reading.
And hope some one can advise.

 

[Lionfish Lair]

The first picture sort of looks like a flatworm. The roots could be hydroids. Fourth is a pineapple sponge. Fifth picture is a munnid isopod.

 

[chubbyhubby]

Thank you are any of these bad for the tank