Help me ID please...

[mdrury]

I have several (N+1) 'sacks' of eggs sticking to the front glass of my 120 Gal. reef tank. Not sure what they are, perhaps someone can help ID them.






I think they may be snail eggs. I have Trochus, Cerith, Nassarius and Astria snails in my tank. I have seen several 'baby' Nassarius snails on the glass, could they be from these eggs?

Also, I have several of these little creatures living in both my tanks, but I would like to know what they are:



Any help Identifying anything would be greatly appreciated.

Thanks,
Murry

[Samper]

The bottom pic looks like a cirolanid isopod.

[Ninong]

Murry,

The first pictures are probably snail egg capsules but I'm not sure of the species. I can tell you that it is extremely unlikely that you saw baby Nassarius snails in your tank because they undergo a period of several weeks as pelagic larvae.

Regarding the critter in the bottom picture, do you have a dorsal view, too? Does it curl up into a ball when you touch it, like a pill bug? Have you witnessed it's swimming mode? Have you seen any of them attached to any of your fish? I'm not convinced that it is a cirolanid isopod at this point but a dorsal view would help.

Here is what a typical cirolanid isopod looks like:

[mdrury]

Ninong,

My tank has been up for several months. I did purchase several adult nassarius snails (both vibex and obsoleta) shortly after the cycle completed, but all where about 4-8 cm in length. Today I took photos of one of the "baby" nassarius, which is about 4 mm long.



The cirolanid isopod you show in your photo is not what I am looking at. I have seen the cirolanid isopod you show burrowing in the sand or playing on the rocks. I appreciate the ID on that one as well.

Here are photos of the unidentified pod on a rock. Sorry I can't take better photos, my camera doesn't like focusing beyond the fron glass.





Thanks again for your help. You also Samper.

Murry

[Ninong]

Ninong,

My tank has been up for several months. I did purchase several adult nassarius snails (both vibex and obsoleta) shortly after the cycle completed, but all where about 4-8 cm in length.

Is that a typo? Because 4-8 cm = 1.57" - 3.15". That's much too big for either Nassarius vibex or Ilyanassa obsoleta. I. obsoleta gets considerable larger than N. vibex but neither gets anywhere near 1.57" long. Most mature N. vibex are about 1/2" long and most mature I. obsoleta are closer to 3/4".

Today I took photos of one of the "baby" nassarius, which is about 4 mm long.

Whatever that is, it does not appear to be a Nassarius or an Ilyanassa species.

Both Nassarius vibex and Ilyanassa obsoleta have separate males and females. The female is fertilized internally by the male before the egg capsule is extruded. The fertilized eggs (now embryos) are covered in a proteinaceous capsule which the female extrudes onto any hard substrate. A few days later the veliger larvae hatch and then spend several weeks going through various stages as pelagic larvae before settling out. It would be virtually impossible for them to survive that long in an aquarium because they would be either eaten or filtered out before they settled.

Thanks again for your help. You also Samper.

Murry

Interesting pics. Can you count the segments on the back?

[Ninong]

Murry,

I took the liberty of posting all of your mystery pics in the Ask Dr. Ron forum on Reef Central because I'm curious to find out what he thinks they are. I'll let you know what he says.

[Ninong]

Murry,

I have a positive ID for you from Dr. Ron on your unidentified "pod." According to Dr. Ron:
They are sphaeromatid isopods, and both images show males.

See here: http://reefkeeping.com/issues/2002-05/rs/index.htm

And before you freak out on the fact that the article also covers Cirolanids, I think I'll post this one quote for you here: One group is comprised of the harmless scavengers in the group called the Family Sphaeromatidae.

So your particular isopod is a harmless scavenger and not a harmful parasitic isopod like the Cirolanids.

[Ninong]

Murry,

None of the snails that you have named are likely responsible for the egg capsules you have pictured. What about your mystery snail, the one you called a "baby Nassarius?" Have you seen anything in your tank that looks like that, only larger?

Dr. Ron's best guess is that your mystery snail is responsible for the egg capsules. BTW, can you give a guess as to the approximate size of those egg capsules?

I may be able to get a positive ID for you on the mystery snail but it would require a clear, in focus picture showing the shell aperture with the animal retracted. The best guess so far is that it is a Columbellid of some sort but that's just a guess without a picture of the aperture.

[mdrury]

Hey Ninong,

First, thanks for helping me identify that pod. I have seen other types of "pods" in the water, but they look like brine shrimp to me. Scurrying around in the rocks, and occasionaly swimming about in the water column.

As for the snail, yes, the shell of the baby looks very similar to one of the snails that was sold to me as nassarius Vibex, that is why I assumed thats what they were. I don't think that the mystery snail is the source of the egg capsules though as he is not bigger than the capsules. Tha capsules are approximately 1-2 mm wide, and contain approximately 20 eggg each. I have only seen about 4 of the mystery baby snails, but there must be 50 or 60 of the egg capsules.

Now that I have prepared a shallow bowl of water and put my camera on a tripod I can find none of them to capture and photograph; but I will post a photo as soon and I find on.

Murry

[Ninong]

As for the snail, yes, the shell of the baby looks very similar to one of the snails that was sold to me as nassarius Vibex, that is why I assumed thats what they were. I don't think that the mystery snail is the source of the egg capsules though as he is not bigger than the capsules. Tha capsules are approximately 1-2 mm wide, and contain approximately 20 eggg each. I have only seen about 4 of the mystery baby snails, but there must be 50 or 60 of the egg capsules.

I didn't mean that the mystery snail specimen in your picture laid those egg capsules, that's why I asked: "Have you seen anything in your tank that looks like that, only larger?"

The Columbellids in my tank are about 1 cm in length when mature, but I sometimes find some that have recently hatched and they are only about 2 mm long. Mine have a reddish foot and they don't look quite the same as the snail in your picture. They were sold to me by IPSF as Strombus maculatus but they are not that. They do reproduce in my tank and the babies look exactly like the adults, just much smaller.

[mdrury]

I took a few more photos of the snail in a small dish, but I couldn't get him to stay retracted or upside down long enough to take a photo of the aperture.





Notice that the snail has the "snorkel" common on Nassarius snails. He may not be a hatchling from the eggs I have, he may be a hitchhiker from the live rock.

Sorry my photos are so poor. The closest thing I have to a macro lens is a 10x jewelers loop held in front of my Sony DCS-P72 digital camera.

Murry

[Ninong]

Murry,

In order to get an identification, we need a picture of the shell aperture with the animal completely withdrawn. You would need to remove it from the water to get such a picture.

In the meantime, here are a few pictures of the snails that IPSF sold me that were supposed to be Strombus maculatus. They are actually Columbellids. The size of the specimen pictured is about 1 cm.







Those pictures were taken in a small pyrex glass dish with about 1" of water.

P.S. -- The snail you pictured is definitely NOT a Nassarius.