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Very difficult to tell but looks like sponge from 1st pic. Do you have any flower like structure in 2nd photo? Like here it looks like you have hydroids as well still not very clear about this. Still if u have flower like structure Google search colonial hydroidsHi everyone,
New here. Can you help me ID some hitchhikers on my live rock?
Thanks everyone!
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It is somewhat difficult to see, but I'd guess that's just the new growth of the sponge.Is it hydroid? Unable to watch this clearly in my phone but it seems like hydroids
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poriferan type sponge known as Syconoid sponge and are harmlessHi everyone,
New here. Can you help me ID some hitchhikers on my live rock?
Thanks everyone!
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The first one is an Aquilonastra starfish (known in the hobby as Asterina - see the super long response below). The second one seems to be a feather duster worm - harmless filter feeder.Thanks everyone! I found a few more that need ID.
Timfish said:
It's an Aquilonastra spp. starfish and is a great scavenger. I see them with anywhere from 4 to 12 legs. The whole discusion around them seems to me excellent examples of misidentification, mistaken behaviour and assumed causality based just on heresay without looking at the research. Asterina spp starfish are preditary but only reproduce sexually and are shortlived so while it's possible some might get into a tank even if it did happen it's not going to be around long. Aquilonastra are one of the uncommon species that reproduce fissiparous or by splitting so are easy to identify by the different sized legs regrown after splitting. They perform an important function not only feeding off algae films but also feeding off microbial films including those on corals (at least ones that don't sting). FYI the mucus coating on corals ages and corals have to periodicely shed it to renew it and maintian healthy microbial processes (Ref 1, Ref 2). If Aquilonastra are feeding on zoas or softies I'll argue they are either benign or even beneficial as they may be reducing the unhealthy older mucus which can be full of unhealthy microbes which the animal is trying to get rid of and are far more likely to be the actual problem.
Here's an example, this Toadstool is doing one of it's periodic sheddings. The Aquilonastra have been in this system for years but only climb onto the Toadstool when it's shedding. In the first picture you can see the old mucus film, Aquilonastra starfish and areas they have cleaned off. The second picture shows the Toadstool a week later.