Coral or some sort of worm???

[ggwp1111]

I bought this AIO tank used locally. While cleaning it, I noticed some stuffs inside the overflow compartment that I couldn't get in there to clean or inspect. Is this some sort of dried up coral or worm/parasites? I just wanna make sure this is safe for me to start transferring my old tank to this new one.

 

[DeniseAndy]

Just scrape with razor blade and some vinegar. Should clean nicely.

 

[moz71]

Got millions in my sump. Some kind of tube worms they are fine. Just scrap off.

 

[tbrown]

I don't think your question has been answered fully yet. Those are worm carcasses. Are they "safe" depends on the type of worm which is hard to determine from the dried up husks. However, as far as transferring the old tank over, my concern would be the potential for an ammonia spike so I'd say to definitely try to get as much out as possible to minimize the decaying matter.

Edit: they look to be miniature/micro feather duster worm tubes. They're a beneficial filter feeder but not when they're dead.