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phxazcraig

What is this? Coral? Hydroid?

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Shot in Roatan in September.190922-104404-0-D850.jpg

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Definitely not coral. Almost certainly a hydroid. Size? Did you touch it, did it sting?

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Hydroids for sure, and looks like a few Skeleton Shrimp hanging about amidst the branches.

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Size - bigger than a fist, but not a lot?  I did not touch it.

Going from the few hydroid examples at Florent's Reef Guide online, I think it may be an Algae Hydroid.   Florents' example even comes from Roatan.

I saw several of them over two weeks. 

I've never heard of Skeleton Shrimp.  Tell me more.  Where do you see them?  I have two other shots about the same but maybe slight focus differences.

PhxAZCraig

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Definitely worth checking out skeleton shrimp. REALLY hard to photograph but they make the most curious of images.

They are usually on hydroids - see attached. They are one of those critters that are very hard to spot - but once you know how to "see" them, hydroids become areas of great interest!

TG46006.jpg

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5 hours ago, phxazcraig said:

Size - bigger than a fist, but not a lot?  I did not touch it.

Going from the few hydroid examples at Florent's Reef Guide online, I think it may be an Algae Hydroid.   Florents' example even comes from Roatan.

I saw several of them over two weeks. 

I've never heard of Skeleton Shrimp.  Tell me more.  Where do you see them?  I have two other shots about the same but maybe slight focus differences.

PhxAZCraig

Yes, I have seen lots of those in Roatan, but never knew what they were.  Now I will have to check them for the skeleton shrimp.  I had no idea that they might be there.  Thanks!

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Yep, they can definitely brighten what might look like an unpromising macro site!

 

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Now that I know what to look for I'm going to be looking closely in the future.   Too bad I'm just finding this out now after I'm done with dive trips for the year.  I've spent 9 weeks over the years diving in Roatan.  I wonder how many times I've missed out here?  I've learned to look closely in and under anemones for crabs and shrimp.   I'll add hydroids.

I think I'm going to need to get a wet lens diopter to get more magnification for shrimp like this and wire shrimp.  

I've been looking at the three images I've got of this hydroid colony, and while I don't think I have any skeleton shrimp in focus, I do think I'm seeing something in a couple of areas.  I'm going to go back, do some 100% crops of certain areas and repost here to see if I'm seeing things that aren't there.   For instance, I think I see something right in the center of the mass, just above the red algae in the center.

PhxAZCraig

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Yeah, isn't it frustrating when you find out afterwards something was there and you've never seen them? Argh.... 

The image I posted was using a 105mm on a D500 - so approx 160mm I guess. It might help with a diopter although the problem I often find when photographing micro-critters is finding them in the viewfinder when using large magnification.

I was shooting pygmy pipe dragons (see image) in Lembeh some years back and thought I was going to lose the plot trying to find them with a 105mm - which is the only way I found to photograph them. They have to be 1/4" long and look like a knot on the end of a piece of cotton.

TG22677.jpg

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I went back through my 3 images of this Algae Hydroid looking for shrimp.   I can't really say I've found anything in the 7-9 clock region, unless the out-of-focus lumps on the end of the 'stalks' are creatures.   Can't tell.   But I am 99% sure I've found two shrimp that I cannot identify in there.   I made extreme crops of the sections of interest.   What I see is a shrimp pretty much dead center in the image, and another one at about the 5:30 o'clock region about halfway out from center.   Both look to have eyeballs on stalks, and possibly black down the center of the back flanked by striped 'rails'.   I also think I see a pair of eyes on stalks at about the 5 o'clock position just outside the red algae center.   I will attach these extreme crops below:

190922-104423-0-D850-1.jpg

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I tried more and cannot upload.  This is a ridiculously small limit for uploading files....

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Since I can't seem to upload even 2mb here, I took the small images and zipped them up together and uploaded to my website.   If you want to try to ID these shrimp, please download and unzip the JPG's from here: www.cjcphoto.net/misc/shrimpid.zip

If needed, I can provide the raw files as well.

PhxAZCraig

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Yes, Looked at your photos and these are indeed the Hy6droid Shrimp, Rapipontonia galena,

that I was referring to that you might also find on these type of hydroids in the Caribbean as well!! They are much larger than the Skeleton Shrimp. which probably look like the unfocused blob areas your referring to. :) Something to look forward to next dive trip then.. Yes, you'll need to add a good diopter for these guys, they are teeny tiny..Tim has a bit of an advantage as those in Indo although still small, are some what  larger than those we find in Cayman, etc..

 Do you dive with AKR by chance while on Roatan? I have a very good friend who works there who excels at macro hunting..

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6 hours ago, Quinn said:

 Do you dive with AKR by chance while on Roatan? I have a very good friend who works there who excels at macro hunting..

I have spent all my time in Roatan at one operation - the Reef House Resort.   I went once in 2008, and went back in 2014.   Started going back every year.  The Divemaster (David) is fantastic at finding things.   We dive well together.  I've followed him on over 170 dives.

 

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