Help with ID please

[jonny_milner]

Can anyone help ID these on my acan frag? There’s a couple on my rear glass as well.

 

[jonny_milner]

Also just noticed this

 

[Billdogg]

spirobid worms and sponge. both harmless IMO

 

[jonny_milner]

spirobid worms and sponge. both harmless IMO

Thanks. The small white things definitely look like spirobid worms. Any idea what sort of sponge the other thing is?

 

[Billdogg]

It's a white encrusting sponge. If it begins to encroach on a coral, you can trim it back fairly easily, but have a siphon tube there next to it when you do. Even a tiny fragment can easily become another sponge elsewhere in the tank.

Unless they are really becoming a problem, I let them be, as I do all the creatures in my tank (well, other than aiptaisia, bubble algae, and other harmful invasive pests).