Don’t know what these are, need help

[kbnh]

Should I be worried about these or are they just filter feeders?

 

[Tired]

Pineapple sponges. Harmless filter-feeders. Explode in population in new tanks, then fade away to more reasonable numbers.

 

[WheatToast]

Pineapple sponges. Harmless filter-feeders. Explode in population in new tanks, then fade away to more reasonable numbers.

+1. The leftmost hitchhiker in the first image looks different though (less fuzzy, more squishy).
@kbnh do you have any more pictures of this hitchhiker?

 

[Tired]

Oh, yeah, that does look a little odd. Given the context (surrounded by pineapple sponges and spirobids), I'd be inclined to say it's probably a chunk of some other species of sponge.

 

[kbnh]

+1. The leftmost hitchhiker in the first image looks different though (less fuzzy, more squishy).
@kbnh do you have any more pictures of this hitchhiker?

I will try to grab pics tomorrow

 

[kbnh]

Couldn’t get a decent picture but it just seems to be a pineapple sponge stuck to the glass on its side