Are these copepods?

[aandrin00]

Hi everybody!

Yesterday about an hour after lights out I noticed a ton of these little guys twitching about in the water column - only noticed them because I have a small peninsula tank so I could look through the water with a light on the far side. I sucked a couple out so I could get a good look and some photos (got a decent video too but I can't seem to attach it to this post). They don't look like what comes up when I search the internet for copepods so I'm curious.

They seem to have 2 dark eyes, no visible antenna, and a clear tail (if you look closely at the photo you'll see that tiny orange line right next to that hair, that's where the tail ends). When I put them in the container I could see that they move in a twitching motion by bending their tail toward their eyes). The 2nd photo with the ruler is just to show scale of the container I put them in (they're not in the photo), their total length is on the order of 1/16". Look to me like tiny shrimp; can anybody please ID these for me? I wish I had a microscope!

Thank you!!

 

[A$AP-Reefer]

Could be a really small pistol shrimp.

 

[aandrin00]

Thanks for the input!
They do indeed look like baby shrimp but I have no idea how pistol shrimp would've been introduced, it would have had to be a huge number of eggs that came in on a frag.. and then they would've had to grow a significant amount. There were hundreds of these in my water last night. Again, only came out after lights out and they were floating in the water column; would this behavior align with that of pistol shrimp?
Thank you!

 

[A$AP-Reefer]

Thanks for the input!
They do indeed look like baby shrimp but I have no idea how pistol shrimp would've been introduced, it would have had to be a huge number of eggs that came in on a frag.. and then they would've had to grow a significant amount. There were hundreds of these in my water last night. Again, only came out after lights out and they were floating in the water column; would this behavior align with that of pistol shrimp?
Thank you!

conversation! There a way you can catch a video or have a picture of the eggs on the frag you purchased. Just the body structure reminded me of it. As for hundreds I am not seccond guessing myself on what I said

 

[aandrin00]

Let's see if this video works.. converted it to a gif.

Also, maybe you misunderstood, what I meant was that for that many pistol shrimp to have come into my tank they would've had to come in as eggs. I didn't actually see any eggs on frags and I've been trying to remove as much of the frag plugs as possible before mounting in my tank. Certainly still possible though. When I saw these I just assumed that whatever it is would be reproducing within the tank.

 

[evrydayzawrkday]

I am fully vested. Can you give an update in a week to let us know the size?

 

[Ricox]

Looks like some kind of small or baby shrimp.

 

[clm65]

Do you have any pairs of any shrimp in your tank?

 

[Jay'sReefBugs]

Isn't moving like a typical copepod

 

[aandrin00]

Thank you all for your input!

Looks like they're all gone. I took a look again after the lights went out last night and didn't see any floating around in the water column. Either the mechanical filtration got them all or they're no longer free-swimming. If I see them again I'll definitely update this post.

I don't have any shrimp in the tank. As far as inverts, just snails and a few hermit crabs. They must have come in as eggs, or whatever they are they're full grown and somehow reproducing within the tank. It boggles my mind that I would've brought in that many eggs on a frag, I thought my dipping game was on point! Always remove most if not all of the frag plug, then bayer and coralRx.

Now I kind of wish I saved some and tried to grow them out.

 

[damsels are not mean]

Looks like crustacean larvae to me. Probably the hermits spawned or one of them came in berried with eggs. For reference, hermit crab larvae look just like baby shrimp. And due to their clumsy planktonic stage swimming they are almost always either sucked up in a filter or eaten by a fish. My other thought was mysids but usually those last in a tank like amphipods.

 

[DaJMasta]

Definitely looks and moves like a larva. Hermit larvae look somewhat like that and have a somewhat distinctive behavior of curling their tails under their body a fair bit - these are some

If it's got a long, thin protrusion out of the nose, it could be a porcelain crab larva. Otherwise, there's at least a reasonable chance it's an emerald crab or similar, depends on what you've got in your tank.

 

[aandrin00]

Awesome! That's exactly what they looked like! I bet it's the hermit crabs; I have a couple blue legs and a couple scarlets. Would be cool to try raising a bunch if I ever happen to notice them again like I did that night. What a coincidence, I just got a container of a few hundred empty shells from Michael's so that the hermits wouldn't kill my snails, gotta put those shells to good use

 

[damsels are not mean]

Awesome! That's exactly what they looked like! I bet it's the hermit crabs; I have a couple blue legs and a couple scarlets. Would be cool to try raising a bunch if I ever happen to notice them again like I did that night. What a coincidence, I just got a container of a few hundred empty shells from Michael's so that the hermits wouldn't kill my snails, gotta put those shells to good use

I think it's hard to breed them but I plan to try soon. First I am mastering live plankton culturing.