Swarming mass o' mysid?

Sierra_Bravo · Jul 28, 2018

I was delighted to find what appeared to be a huge swarm of mysid shrimp in my tank late last night.

A couple of questions:

Are these indeed mysid shrimp?
Was there a hatch or are they spawning?
I've just never noticed them before - how were they introduced or have they probably always been in the display (Gulf of Mexico harvested live rock - been in the tank over a year)

Whatever they are and however they came, it seemed that the corals were going crazy while they were out.

Instigate · Jul 28, 2018

Video is not working. Do you have any emerald crabs? When I first saw the spawn from my emerald crabs I mistook them for shrimp.

Nano sapiens · Jul 28, 2018

FYI - Video is unavailable

I've had them for many years. They started to appear a month or two after I began using frozen mysid shrimp. I suspect that not all frozen mysid contains via eggs (especially those from companies that irradiate/sterilize their products), but some seem to.

Sierra_Bravo · Jul 28, 2018

Hmm. . .video is working in my browser. I changed permissions, maybe that will help.

No emerald crabs and I do use frozen mysis.

Instigate · Jul 28, 2018

Now that the video is working definitely not emerald crab spawn. Maybe just pods? Kinda looks like some pods I recently had ID'd. https://www.reef2reef.com/threads/tiny-worm-or-crustacean-id-please.421272/#post-4909406

LadyMac · Jul 28, 2018

Whatever they are, they look cool! I don't think I have any real friends like such in my setup. Would be super cool to find something so prolific.

Instigate · Jul 28, 2018

LadyMac said:
Whatever they are, they look cool! I don't think I have any real friends like such in my setup. Would be super cool to find something so prolific.

Do you ever check at night?

LadyMac · Jul 28, 2018

Not really, no. I could try tonight when lights are completely off and use a flashlight to check.

Sierra_Bravo · Jul 28, 2018

Instigate said:
Now that the video is working definitely not emerald crab spawn. Maybe just pods? Kinda looks like some pods I recently had ID'd. https://www.reef2reef.com/threads/tiny-worm-or-crustacean-id-please.421272/#post-4909406

I wish I had been able to focus the camera better but they had the body form of a shrimp and were definately swimming. The light was making them congregate on the glass.

Sierra_Bravo · Jul 28, 2018

LadyMac said:
Not really, no. I could try tonight when lights are completely off and use a flashlight to check.

You would be surprised at what comes out at night! I have a regular, red and blue lens flashlight I keep by the aquarium and use them frequently. It's a completely different tank after the lights go out.

Instigate · Jul 28, 2018

You might msg a mod to move this to the hitchhiker ID section, you might have better luck with the people that monitor that forum. But for now I'll tag @KJ and #reefsquad

ZoWhat · Jul 28, 2018

Look like copepods to me?

What fish do you have.... any Wrasse would think it's a 24/7 week long visit to Golden Coral

Sierra_Bravo · Jul 28, 2018

skimjim said:
Look like copepods to me?

What fish do you have.... any Wrasse would think it's a 24/7 week long visit to Golden Coral

They were more shrimp-like than that photo. I'm fairly certain after looking at images they were young mysid.

As far as fish, if that swarm went into the rocks this morning I have a mystery wrasse and a couple green banded gobies that are going to have after Thanksgiving meal-sized stomachs today.

justin.k.nelson · Jul 28, 2018

That is pretty cool. Nice food for big mouths

Diesel · Jul 28, 2018

Lots of nutrients rich fish food

is what I see

Instigate · Jul 28, 2018

Sierra_Bravo said:
They were more shrimp-like than that photo. I'm fairly certain after looking at images they were young mysid.

As far as fish, if that swarm went into the rocks this morning I have a mystery wrasse and a couple green banded gobies that are going to have after Thanksgiving meal-sized stomachs today.

Aren't mysis freshwater though?

/wiki says they're also brackish, so maybe.

saltyhog · Jul 28, 2018

Instigate said:
Aren't mysis freshwater though?

/wiki says they're also brackish, so maybe.

Mysis are fresh water, mysid are salt water

Instigate · Jul 28, 2018

saltyhog said:
Mysis are fresh water, mysid are salt water

That's funny, every time I saw mysid I thought people were misspelling mysis. Smh

rossco · Jul 28, 2018

I have had my hermit crabs release young that look like that. The crab stretches out of its shell a bit and you can see all the babies in there and then it snaps the shell forward and propels them out. They swarm toward light and are usually gone by the next night.

Sierra_Bravo · Jul 28, 2018

rossco said:
I have had my hermit crabs release young that look like that. The crab stretches out of its shell a bit and you can see all the babies in there and then it snaps the shell forward and propels them out. They swarm toward light and are usually gone by the next night.

Now that would make more sense. No shortage of hermit crabs in my tank, and looking up crab zoeae it is quite possible that's what they were.