Here’s a little clip I shot this week on Okinawa Main Island’s Pacific coast (Kin Red Beach) — a classic but colourful commensal / symbiotic combo: Emperor shrimps (Zenopontonia rex) riding their lofty nudibranch palace (?Ceratosoma trilobatum?).
Edited to “Raindrop” by Tomotsugu Nakamura (sound on if possible)

This was shot on my old Lumix LX10 compact in 4K/30fps, using either the Nauticam CMC-1 alone or stacked with a UCL-165 close-up lens.
Lighting was from two Kraken Hydra 8000 V2 lights and one Backscatter MW4300. There was a bit of water movement and suspended silt, so I'll need to be more careful with light placement next time using the triple-light setup...

Cheers and happy bubbles,
Ben

Edited July 1, 2025Jul 1 by bghazzal

Amazing quality images and perfect editing. Bravo!

I see one of the shrimps goes down to the nudi's feeding mouth. Does it eat the same things?

Thanks

Nicely done, Ben! Thanks for sharing

I liked it a lot!

12 hours ago, bghazzal said:

(?Ceratosoma trilobatum?).

That's Ceratosoma tenue, (broken purple margin and third mantle lobe on the side)

Apart from that, very nice footage.

11 hours ago, Davide DB said:

Amazing quality images and perfect editing. Bravo!

I see one of the shrimps goes down to the nudi's feeding mouth. Does it eat the same things?

Thanks

Thanks a lot, Davide! I'm happy to have found a new playground after the move over here.

From what I understand, the shrimps mainly feed on detritus and mucus from the nudibranch as it feeds, as well as any bycatch it dredges up from the sand.

5 hours ago, Troporobo said:

Nicely done, Ben! Thanks for sharing

Thanks, really appreciate it! This one was fun to shoot and put together.

5 hours ago, Nikolausz said:

I liked it a lot!

Thanks! Glad it landed well.

2 hours ago, Luko said:

That's Ceratosoma tenue, (broken purple margin and third mantle lobe on the side)

Apart from that, very nice footage.

Thanks Ludo, and cheers for the ID and mantle details — great info. I’ve edited it; should have asked sooner! 😊

I've never heard of this dive site in Okinawa! Do many dive operators do this dive? I'll have to come back soon.

1 hour ago, bghazzal said:

Thanks a lot, Davide! I'm happy to have found a new playground after the move over here.

From what I understand, the shrimps mainly feed on detritus and mucus from the nudibranch as it feeds, as well as any bycatch it dredges up from the sand.

First of all nice work, must be quite the task lining all this up with the water movement and the short working distances.

I think most Ceratosoma sp. feed on sponges storing the toxins from their prey in glands. The shrimp I expect make use of "safe" transport as the nudis are left alone as they taste so bad. I expect there is no shortage of detritus around the the nudi and the shrimp happily feast on it as the nudi travels to new locations. They seem to be picking up little particles as they move about the nudi and the one underneath just taking advantage of what is stirred up.

5 hours ago, Chris Ross said:

First of all nice work, must be quite the task lining all this up with the water movement and the short working distances.

I think most Ceratosoma sp. feed on sponges storing the toxins from their prey in glands. The shrimp I expect make use of "safe" transport as the nudis are left alone as they taste so bad. I expect there is no shortage of detritus around the the nudi and the shrimp happily feast on it as the nudi travels to new locations. They seem to be picking up little particles as they move about the nudi and the one underneath just taking advantage of what is stirred up.

Thanks Chris! Yep, it definitely took a bit of patience — the movement and focus distance were tricky, but the action and interaction going on made it a fun challenge.

That explanation makes a lot of sense.
Yes, the shrimps were constantly picking at particles drifting by or on the nudibranch’s body, and it looked like they were competing for the spot near the feeding mouth. Really interesting behaviour to watch unfold — seems like a pretty efficient little system.

Nicely done Ben! Lovely work.

22 hours ago, shokwaav said:

I've never heard of this dive site in Okinawa! Do many dive operators do this dive? I'll have to come back soon.

It’s on the east coast (Pacific side) and one of the best muck/macro shore sites here, I think, the other being Tengan Pier. I don’t know the seawall sites well yet (there seems to be a lot of good stuff in Sunabe, especially on night dives), but the diversity of habitats there is quite special.

Not sure how many operators dive it — the main east-coast one is Crystal Blue, I believe — since it's a bit off the beaten track for most, being on the east side and also a macro-focused shore dive with often iffy to low visibility.

We can always dive it together next time you’re around. It’s pretty easy to get tanks for shore dives here — rental’s about 550 JPY on average for a 10L aluminium or steel tank. The rest just comes down to car and weather logistics.

15 hours ago, humu9679 said:

Nicely done Ben! Lovely work.

Cheers Craig, appreciate it 🙏

Edited July 2, 2025Jul 2 by bghazzal