What the heck are these?

[Fishguy2727]

This thing popped out one day while I was feeding. I was able to get two pics and one very blurry video (not worth anything). Poked its head out and then darted back in real quick. Its hole reminds me of the spider web of a spider that makes its web right in a little crevice with only the whole and a little web showing. It is about 3/4-1" long.



These are growing on the glass. They are not growing where light is hitting them, mainly behind the rockwork on the glass. They are also in the skimmer. They are about 1/4" long. No movement like they are actively filter feeding.

[kaybee]

The stuff on the glass are a type of sponge, beneficial filter feeders ('pineapple sponges', I believe).

[Fishguy2727]

Sweet, that makes three types of sponges in my tank, and I like pineapple.

[rageybug]

Those are definately pineapple sponges. They will come and go depending on your tank's water quality. They can get pretty big, about the size of a pencil eraser. As for the other thing, looks like some kind of worm.

[snapdragon9]

are pineapple sponges relative to good water quality?

[unleashed]

ditto with the above

The other is an amphipod.