Mushroom critters - need help identifying

[LMFisher]

Hello all I am new and this is my first post but wanted to see if I can get some help i just recently bought a mushroom and i know they carry stuff sometimes and night time is when they come out so i decided to check on it and noticed some critters that I nervous might be harmful to the tank. Please refer to pictures!

 

[ISpeakForTheSeas]

The white blob in the top left is probably a pineapple sponge (blobby things are much easier to ID in the water though); the white lines are feather duster worm tubes; and the little, white, spiralled dots are Spirorbid worm tubes (a kind of feather duster again).

All of them are harmless.

I also, however, see some bubble algae (the little green bubbles that look kind of like eggs) on the right - there's one big one (and possibly a couple really small ones) at the base and three smaller ones visible sticking off the right side there. Bubble algae is considered an invasive nuisance, so removal is generally recommended.

 

[formallydehyde]

In addition to what ISpeakForTheSeas said, the circled things are amphipods which are harmless. (I am certain about the one circled on the left but the one on the right is harder to see, however the color and rough body shape makes me think it's just a slightly smaller amphipod)