algae? sponge?

Hello! First time posting here. I've searched everywhere and can't find anything like this. Uncle thinks it may be a sponge, but I don't see any openings like most sponge have. Looks like slime with small branches in it. It has gottena little bigger since this picture. This is ona love rock on the side of the tank. Also a smaller one on opposite end of the tank. Also wondering about the feather duster looking things on the 2nd pic. Found some similar pics but still not sure if good or bad. There area lot of them. Thanks in advance!

 

The first critter looks like a sponge of some sort...there are many types that crop up here and there. The critters in the second photo are Serpulid fanworms...harmless filter feeders.

Here's a link to our PICTORIAL HITCHHIKER ID GUIDE that may help in the future...just match your critter to a photo, and there's your ID.

 

sponge and sabelidae worm, both harmless

nice little list there greg

 

Thank you both.