BC2008 - Mandarin - Witt - I'm in the game!

[Witt]

After talking with Matt about breeding mandarins and watching his spawning videos and gazing at his larval pics I decided it was time to try. So, a few weeks ago I picked up a couple male mandarins and awaited some females at the fish shop. At first, I cursed these fish as I could do nothing to get them interested in frozen foods. So, I said the hell with it and set them up in 'Seagrass, biotopes'...where the nightly swarms of copepods offered a sigh of relief that there might just be enough food in there. Well, it has been 2 weeks since adding straggly little females to the tanks, and last night, ironically enough after downloading and listening to my podcast with Brian on 120 gallons, I noticed that the little female was no longer straggly - in fact quite rotund. For those who haven't heard it - Matt P. asked why mandarins were not in the book. I thought it was very fitting that there first spawn occurred at this podcast release. 15 minutes after the 'bright' lights went off, they made their first assents- quite ackward at first, but they eventually got the hang of it and gave me about 65 eggs. Stay Tuned!!!


This is the first assent and a lousy shot, but I had to show you something Matt!

This is 3 hrs. after fertilization. I needed to know if they were fertile so I rushed them off to a microscope at midnight. This is very exciting! I have spawning mandarins and I have yet to feed the tank. How cool is that. It's like one of those little sealed glass bowl ecosystems.

[Witt]

I was delighted this morning to see that the eggs were in fact developing! This is roughly 10 hrs. after spawning...

[mpedersen]

GO GO WITT! Is this going to be your Breeder's Challenge thread then?

Mat

[KathyL]

So two weeks of good feeding is all it takes? Woah!

[Witt]

Less than 24 hrs. later we have larvae-
Incubation thus far has posed few difficulties. I really wasn't going to try raising this first batch as my schedule has been quite full lately, but curiosity is killing me as i want to see what these little critters will look like in one more day!

It is pretty cool to see the prolarvae with overhead light- nice yellow colours on them.

[KathyL]

Awesome!

[mpedersen]

Witt, those are some AWESOME pictures! I can't way to see what you get out of them as they progress. What would you say your hatching success rate was, and what method did you use to incubate the eggs through to hatching?

(suddenly I'm feeling not-so-far ahead of the curve anymore )

Matt

[DrHsu]

Cool pics, Witt! What's the background in those pics - a counting grid?

Nice to know that even seasoned breeders get excited over their first spawn of a new species

[Witt]

I am really getting into this mandarin game, and this little pair is quickly moving up on my list of favorite fish. The female didn't look so plump today so I wasn't holding my breath for another spawn, but sure enough around 8pm she started hydrating and became quite plump over the course of an hour. I got the camera ready and each time the pair looked like they were gonna make a go, they split up. This might be my favorite part - as I have yet to get a decent shot of the assent. I figure if I keep posting my attempts it will keep track of how many times they spawn. So this is spawn number two - a day after the first.

And of course another egg shot. An hour or so after the first egg shot.


DrHsu- the slide is a Sedgwick-Rafter counting slide. The grid is 1mm. Ordinarily, I hate shooting pictures on it, but it does help keep track of size in old files.

[Witt]

Some interesting notes - and details...This should be fun, as my method is already very different.

The tanks is a 46 bowfront with two outside power filters, a mess of live rock, caulerpa, chaeto, and misc. seagrasses. Two 65watt PC, and 2 moon lights on 14hrs. I feed NOTHING to the tank - and do water changes every third week. These are the only fish in the tank and the copepod population is blooming. At night there are swarms in the crevices and at the surface. Amphipods are everywhere as well!
Spawning in this pair, at least the last two nights has been at the surface, literally with their backs out of the water. They do not initiate the assent until they are at the top of the rocks, which are only 8 inches from the surface. I would say egg production is still less than 100, but fertilization and hatching rates are above 90%. I incubate in acrylic conicals (similar to those used for Artemia hatching, but cone shaped, with no seams) for 15 hrs. then straight into a 50 gallon tub. From here, we will see what happens.

[mpedersen]

Incubating in the cone, what temp, what circulation (if any), and what hatch rate? I've observed high fertilization at times, but it seems like hatch rates don't always follow through in the mandarins, and I noticed that things worked best for me with no circulation and temps that were slightly warmer than the broodstock water...hence the questions

- edit - just noticed you said hatching was at 90%

Matt

[quantim0]

Saw these little guys today and they are really cool looking, so tiny though. Hopefully in the next few weeks Matt can start seriously working with them.

All I need now is some Centropyge eggs.

[mpedersen]

Witt, I have something that may be interesting for you - several months worth of data recording their spawning frequency in a spreadsheet. Obviously couldn't observe every last night, but I believe I marked off those days when I couldn't check for eggs / spawns.

If I can dig it up, I'll post it up to the forum or something!

Matt

[Witt]

Keeping with the daily flow - this is a larva from the first spawn, now at 2 dph. Placodes are visible, the finfold is growing dorsoventrally, and the yolk volume has been reduced to half. They mainly drift motionless with the current, and every 20 or so seconds give a good tail burst toward the surface.



My temps are a bit low at the moment (~73F) due to some cold snaps and bad insulation, but the larvae seem to be doing ok so far. Judging by their development I expect they should initiate feeding tomorrow. The second batch of eggs is developing quite nicely as well. The eggs are in ~ 3 gallons of water with ~ 100 mL/min of air flow from an open ended airline.

Matt P. has accumulated an incredible wealth of data from his spawning mandarins. It looks like my pair has a while to go before I see some real egg production. Thanks again Matt.

[Witt]

One more thing I forgot to mention about the broodstock tank. The idea of a refugium has been talked about for some time now, and its benefits are well documented for reef tanks, and many advocate there use as a source bed of copepods and amphipods for fish such as mandarins. Well, I have been using an idea similar to this for a long time now to keep pod populations up. The outside power filters are AquaClear 700s with nothing but the foam blocks stacked up in the back. The foam, the backbone of the system, offers mechanical and biological filtration, but perhaps its most notable function in this system is to offer a refuge for a MASSIVE population of amphipods, polychaetes, and harpacticoids. I rinse the foam in seawater once a month to get rid of the 'gunk' and it is shocking to see how many bugs are in there. At night you can see the shower of pods entering the tank. Pretty cool!

[Spracklcat]

Super, super photos Matt! Can you tell us a little about your microscope/camera setup?

[Peter Schmiedel]

Matt,

stunning pic's !
Keeps my head up after the recent losses I had to face ...

[Witt]

Hello everyone! Today marks day 3 for the first batch and still, no mouth, no eye pigment, and only a trace of a digestive tract. The dorsal view is pretty neat with the developing pectoral fin buds. The dorsal and anal finfold have grown in well, replacing the exhausting yolk. Well, I guess tomorrow may be the big day for feeding. Also, last night I was consumed by work and forgot to hit the pumps for the nightly (?) spawn. I heard splashing only in time to see the eggs getting sucked up by the filter. oops! That would be #3.

I know I am not exactly inventing the wheel with mandarin development, but man it is neat watching these little guys develop. I finally know what the addiction is all about.

As for the pictures... They were created with a Sony DSC-W7 - my trusty workhorse for the microscope. It is attached to an Olympus BH-2 transmitted light scope with a 150 Watt fiber optic light source to bring out the true colour. Check out Scoptronix for the attachments.

[mpedersen]

The slow development has to be the temps - at 73F, you are probably 9-10F cooler than where I had been working with my larvae!

Matt

[Witt]

Wow, what a difference a day can make. I was so excited peering into the microscope this afternoon. A tiny little mandarin, still less than 2mm in length, glowing yellow under the light. But today they have pigmented eyes and a very prominent mouth. Wow! Very cool. So of course, since they have a mouth to feed and eyes to see I had to feed them. Rotifers to 5/mL and a fresh batch of zooplankton to bring it to around 7 total prey/mL. So now for the coolest part. In order to see these tiny little critters I have to put my face practically in the water. Sure enough, they were eating. There tiny little yellow bodies bending into S patterns and striking forward. What a fulfilling sight!

[espenlg]

I just love your pictures! Keep'em coming!

[mpedersen]

So now for the coolest part. In order to see these tiny little critters I have to put my face practically in the water. Sure enough, they were eating. There tiny little yellow bodies bending into S patterns and striking forward. What a fulfilling sight!

SWEET! Striking at rotifers?

Matt

[Witt]

At this point who knows...I have sacrificed quite a few already so I am hesitant to check guts on these ones. I am really excited just to see how far I can take this first batch. From there, hopefully I will identify some potential pitfalls and start collecting guts on future broods.

[DrHsu]

Wow! What a difference 24 hrs make! It's amazing how much development occurred over the last 24 hrs - a totally different looking beast. Looking forward to more daily pics!

[aantreklik_jared]

Any updates?

I have been checking this thread every couple of hours with extreme interested... Love the development pics Witt!