Something spawned... there are tons of mosquito larva looking wigglers!

Los · #1 01/30/2004, 03:26 AM

If anyone can help me identify what just bred in my tank, I would much appreciate it.

I have a 240 reef with various fish:

2 clarkii clowns
7 royal grammas
2 firefish
1 psychadelic mandarin
lots of blue and red legged hermit crabs
1 fighting conch
3 sand shifting star fish (two of which were mounted on top of eachother recently)
2 brittle stars
lots of soft and hard corals
1 peppermint shrimp
5 emerald crabs

So, this evening about 5 minutes after the lights went out, I went to the side of the tank with a flashlight and there were dozens and dozens of little wigglers swimming towards the light. They were only 1-2 mm in length and the twitched just like mosquito larva. It looked like they had a tail, which provided the twitching motion. After I stopped jumping up and down, I noticed that a bunch of them were coming out of the body of a red legged hermit crab that was perched right near the light I was shinning. It looked like it had a mass of the wigglers, although it soon got spooked by the light and it turned around - so I couldn't see if they were coming out anymore. Still, there were lots and lots of these guys and they could swim quite effectively against the current and towards the light.

I collected a dozen or two of the wigglers and put them in a 55 gallon green water tank, hoping that they would survive their plankton stage.

And then I started thinking...

I better make sure that these are OK and not really parasites. Paranoid? Yup. The last time I had something breed, it was the two bright pink nudibranchs that had left half a dozen egg masses in a week. I read up on them and soon learned that's why my leather was getting munched on and I immediately disposed of the nudibranchs and all the egg masses I could find. It's conceivable that I could have missed one of the masses, but the adults haven't been in the tank for two months, so I don't think that is it.

I did a search here and couldn't find anything about hermit crabs breeding, so now I'm worried these might be parasites. I periodically (every week or so) find a dead hermit crab, with its legs still attached to the body - which has been totally eaten except for some scraps and is outside of the shell just lying there lifeless.

Are these wiggling little guys parasites or larva? What did they come from?

If you know what these might be, please tell me what action I should take.

Thanks in advance.

LOS

Los · #2 01/30/2004, 03:37 AM

Update. 30 minutes later there are still dozens of larva in the tank, although now they are swimming just like minature fish. They can swim quite well against the current and they are no longer "twitching" like mosquito larva.

What could this be?

LOS

finding nemo · #3 01/30/2004, 04:14 AM

Wow, how exciting, I hope, if you could take some pics it would help.

Los · #4 01/30/2004, 05:09 AM

Thanks, Finding Nemo. I tried to take some pictures, but the guys are just too small.

After about an hour, I could only see a few of them. Some of them were still "twitching" like mosquito larva near the bottom and others were swimming just like fish. I caught one of the latter near the top using a turkey baster and then poured it out on a plate. The little fish looking critter was really small, but he looked exactly like a minature fish. His two big, black eyes were very visable, but the rest of his body was almost totally transparent.

After two hours, I couldn't see any of the little guys swimming or twitching around.

I'm almost certain that these are not parasites, but then what could they be? I forgot to mention that I also have a large tube worm, but I doubt that is it.

Somebody please help!

Tks,

LOS

RicksReefs · #5 01/30/2004, 06:09 AM

try a search for 'gammarus shrimp' or 'copepods',
here's a start;

http://reefkeeping.com/issues/2002-10/rs/index.htm

Costazul · #6 01/30/2004, 07:19 AM

Peppermint shrimp. I'm sure 90%

sabodish · #7 01/30/2004, 08:22 AM

maybe your clowns spawned....thats exactly what my fry sound like after my saddlebacks spawn

MaryHM · #8 01/30/2004, 09:29 AM

We had emerald crabs spawn in our system and the larvae looked like mosquito larvae.

saltwater-nut · #9 01/30/2004, 09:48 AM

We had a similiar thing happen a month or so ago. Ours turned out to be copods. Weird how their eyes shine like deer in headlights. They are still in the tank. More noticeable at night when the MH's are off.
They remind me of polywogs.lol

Roy

Anemone · #10 01/30/2004, 03:39 PM

My first guess - hermit crabs. Next time it happens, look toward the top of your rockwork for a hermit. They usually climb onto a rock point and lift their shell up a bit, then slam it down, shooting out a bunch of larvae - you'd be surprised at the numbers of larvae a fairly small hermit can put out.

Second guess - peppermint shrimp - if you've had the shrimp less than 6 months or so, or had a second shrimp in there in that time, there have been anecdotal reports that indicate that some ornamental shrimp can store sperm for a while after their last contact with another of the specie. If it's your shrimp, you should be able to find the shrimp "brushing" the larvae out from their attachemnt area on the shrimp's swimmerettes (swimming legs under the tail).

Third guess: your clowns. Only a third guess because you would probably notice if the pari of clowns was guarding an egg nest. If it's your clowns, they'll do it again. In the next couple of days see if they're hanging around anyplace in particular on your rockwork. If they are, look for the bright orange egg mass (it will darken to a silvery color after a few days). The eggs generally hatch in about 10 days (depending upon species and water temperature).

Good luck ID'ing future wigglers.

Kevin

Anemone · #11 01/30/2004, 03:42 PM

I just re-read your list of fish and critters. It could also be the emeralds, or the royal grammas. Check out if any of your RG's have paired and have staked out an area of the tank as their own. Watch for a RG to be decorating a hole in the rock/nesting site with pieces of macro algae...

FWIW,
Kevin

Los · #12 01/30/2004, 03:46 PM

Wow, excellent advice. It's incredible that so many different things can look the same when they spawn.

As a quick update, all the babies apear to be gone.

The peppermint shrimp has to be ruled out, because there is onlyl one of them and I believe there have to be two.

The clown fish haven't paired yet and I didn't notice any nesting behavior.

The hermit crabs, if they can produce larva that look like baby fish, are likely the parents, because I saw the babies coming out of one of them - just as anemone described.

But, I also have recently seen my royal grammas making a nest. The really big one has been putting macro algae and other stuff in a whole.

Can the fry from royal grammas and hermit crabs both look like baby shrimp?

I love this hobby.

LOS

Donkeykong · #13 01/30/2004, 03:53 PM

If you saw them come out of the hermit then my bet is that it is the hermits.

Los · #14 01/30/2004, 05:47 PM

Donkeykong-

I would agree with you about it being the hermit crabs, but I did a search and I couldn't find anything about them breeding. It just seemed kind of weird that hermit crabs would have babies that looked exactly like baby fish.

Has anyone else had this happen?

Thanks again. The help on this board is awesome.

LOS

this_reefer · #15 01/30/2004, 05:57 PM

I agree...it could be your hermits. I had several hermits spawning and I would get tons of small larvae like you describe. But unfort. none of them survived.

Los · #16 01/30/2004, 07:17 PM

Has anyone successfully raised them?

fishinchick · #17 01/30/2004, 07:29 PM

Carlos,
I had the same thing happen in my Nano tank about two months ago. They lasted for about 1-12 days wiggling around like little polliwogs.
I have no Clowns, hermits, crabs or shrimp in my nano. I did have mysis shrimp, copepods and amphipods though. I had snails, a purple firefish and a yellow clown goby at the time.
Several people here looked at them and we even pulled out the microscope and to the best of our guess it was the Amphipods spawning that particular night. These were bigger than copepods but we did agree they werent as big as amphipods.

jonny1972 · #18 01/30/2004, 07:40 PM

I've had these before also. In my tank I have two emerald crabs and some hermits. I've only one fish a redlip blenny. I don't know what they are but they are only seen seldomly and usually for one or two nights only.

Los · #19 03/02/2004, 11:49 PM

Update:

I am now 90% sure that I was actually having two seperate things breed in my tank at once. The twitchy mosquito larva things were almost certainly the hermit crabs, since I saw them coming out of one of them.

What made things difficult is that I had never before looked closely at my tank at night. I thus missed the fact that almost every single night I have babbies hatching.

Since then, I've noticed that I have the fish looking guys just about every night. They hang out near the top, swim just like fish, and are clear with black eyes. They hatch every night right at lights off and then last for a couple of hours at most. Soon, they are eaten by the corals or sucked into the overflows.

So why do I think it's the grammas? Because the females form a harem around the dominant male and are obviously gravid. The male has made, and keeps, a nest just as described by breeders. Most importantly, they constantly exhibit breeding behavior and there are babies just about every night.

Anemone was right!

Thanks,

LOS