Need help identifying these on my Blastomussa skeleton.

[The new fish on the block]

Just noticed all of these hitchhikers on the skeleton of my blastomussa, I don’t know how I missed these when dipping.

These are what I am most intrigued by, I’m guessing hydroids, but I have never seen any with neon green mouths like this:

 

[Gumbies R Us]

@ISpeakForTheSeas

 

[ieatbugman]

It actually looks really pretty, If those aren’t harmful. Also the black sponge is really cool

 

[The new fish on the block]

It actually looks really pretty, If those aren’t harmful. Also the black sponge is really cool

I agree, if they aren’t bad or invasive I will be keeping them!

 

[ISpeakForTheSeas]

Just noticed all of these hitchhikers on the skeleton of my blastomussa, I don’t know how I missed these when dipping.

These are what I am most intrigued by, I’m guessing hydroids, but I have never seen any with neon green mouths like this:

Wow, there's a lot going on here. I see:

-A serpulid feather duster worm tube (harmless)

-A pineapple sponge (harmless)

-A white sponge (probably harmless) with anemones sticking out if it (these are probably not so harmless, but they're pretty neat looking; some people set up separate little tanks for hitchhikers like this)

-A black sponge (probably harmless)

-And what are most likely some hydroid polyps (again, probably not harmless) on the right.


There may be more, but I can't see it on my phone screen clearly enough to say for sure. Anyway, to determine if the non-pineapple sponges are harmless or not:

Most sponges are completely harmless/beneficial, but some can be invasive and/or harmful to corals (thankfully, these are rare).

To tell if a sponge is chemically harmful: if a healthy, established coral starts closing up or looking to be in bad shape on the side closest to the sponge as the sponge grows closer to it, and nothing else has happened (lighting changes, parameter swings, pests, etc.) that could explain it, then the sponge is probably chemically harmful.

Chemically harmful sponges are very rare.

For invasive sponges: unless it shows signs of being chemically harmful or starts actively growing over and smothering a coral's flesh/polyps, it's harmless. These can grow over the skeletons of corals, around the base/stalks of corals, even up into the water column above corals (where they're over the coral but not growing on the flesh or polyps themselves), etc. without harming the coral at all - as long as the coral flesh and polyps can get food, light, and flow, the sponge is harmless.

Invasive sponges are moderately rare.

Invasive and chemically harmful sponges are incredibly rare.

 

[The new fish on the block]

Wow, there's a lot going on here. I see:

-A serpulid feather duster worm tube (harmless)

-A pineapple sponge (harmless)

-A white sponge (probably harmless) with anemones sticking out if it (these are probably not so harmless, but they're pretty neat looking; some people set up separate little tanks for hitchhikers like this)

-A black sponge (probably harmless)

-And what are most likely some hydroid polyps (again, probably not harmless) on the right.


There may be more, but I can't see it on my phone screen clearly enough to say for sure. Anyway, to determine if the non-pineapple sponges are harmless or not:

thank you so much for the detailed response!