Pearly/Yellowheaded Jawfish - Larvae batch #4

Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby llasseter » Sun Nov 08, 2009 6:35 am

Hi all,
I guess I have decided to no longer sit on the sidelines and list my recent experiences about breeding marine fish. :)
I do this as a personal venture, since I am a reef tank fanatic I guess, but I am also a grad student in biology, so hopefully I can get a good paper or two out of this someday if I can do it sucessfully. We need more scientific data published in our hobby, hopefully I will be able to add some someday. On to the experiences......
About 10 months ago I purchased a mated pair of pearly jawfish Opistognathus aurifrons to attempt breeding.

My setup is as follows:
29gallon AGA tank, custom drilled, custom back left overflow
connected to a 45gal sump, that also runs my 90g display, and 14g frag tank.
Current USA 48w T5 HO fixture
5.5" DSB, with liverock placed in the substrate to prop up the liverock on top.
Temp 76.5-77.5F,maintained by 1/3HP chiller on the 90.
pH 8.10 minimum, maintained by Kalk Reactor/Doser in the sump (highest I have ever seen in the combined system is maybe 8.3)
Sump has a ~20gal refugium with 8" DSB, tons of chaeto, and LR w/ a 80w PC light, helping to keep the water chemistry stable.
12/12 Light Cycle

Once I received the jawfish, they were initially placed in a 12g Aquapod I have, as my breeding tank wasn't setup yet. They stayed there maybe a month while I got everything in order, and they moved to their tank sometime in february. In both the 12g, and in their private 29g, they shared a burrow. After a few months in the new tank, one of the jawfish moved out and made their own burrow in the center of the tank, leaving what I later found out to be the male on the left side in the original shared hole. I waited and waited for breeding to start, and after about 6-7 months I decided they might not breed so I added a few more fish to the tank. I guess that kicked them into high gear, because around late August/early September, to my surprise, the male had a mouth full of eggs! I quickly scrambled to get something setup to house the larvae, but my male ended up swallowing the first batch of eggs, I am guessing because they might not have been viable. I was really bummed after he swallowed the first batch, because I thought the breeding cycle might not be consistent, but I was really excited again when I noticed after roughly a week he had a new batch of eggs in his mouth. I ended up missing this batch because they hatched out a night I had already checked his hole and found it covered. He must have come out later and released them. Lucky again, he had another clutch of eggs in his mouth less than a week later.

Larvae batch #1
I patiently watched, and read the breeding page here at MOFIB to get prepared for this batch. When he had the first batch of eggs in his mouth, I went to Tallahassee and picked up a batch of S/SS rotifers to feed with, and had them stored in the fridge hoping for a next batch. By the time larvae batch #1 hatched, (took forever to collect! all over the tank, maybe 150 of them), the rotifer culture was no longer viable due to prolonged storage (3-4 weeks), so I didn't have enough to feed them, and they eventually died by day 4-5, to the best of my knowledge because of limited food availability.

Larvae batch #2
Maybe 3-4 days later, on Oct 7th, I noticed a new batch of eggs in his mouth, which he released on 10/22. (15 days seems a little long, so he may have swallowed the batch i noticed and had another, the 8-10 range on the breeding page seems to be the most accurate in my experience). This time I was better prepared. I had a L-strain rotifer culture to work with for this batch, as I couldn't get anymore S-strain, and couldn't seem to find anywhere to order them, so I crossed my fingers.

Day 1 - Once they hatched, I moved them to a 5.5g AGA tank (blacked out sides), with a 25w heater set on 75, and foam filter. The foam filter is the yellow ring kind you get from FAF, the ones with a yellow doughnut of foam, around a central stalk, which I slowly had bubbling, maybe 1-2 a second. I did 50% daily Water Changes on the larval tank.
Day 2 - Mortality on seemed to be a lot, but I thought the bulk was probably just some of the inviable ones, plus some of the weaker larvae. Probably about 50 of the 200 or so larvae needed to be siphoned out.
Days 3-5 - Everything seemed to be going better. I fed 1/3 of my live culture a day, plus some frozen rotifers, because my culture was kind of small. Less mortality, maybe 20 a day here, but still a lot. I kind of figured that they were eating the Rotifers, because most of the batch was still alive. On day 4 I also noticed the pH was 7.8 and the Ammonia was about .5, and then after a 50% WC, on Day 5, the Ammonia level was 1.0. I siphoned out all the rotifers from the bottom, probably mostly leftover frozen I had been feeding, and started doing larger water changes, by slowly trickling the water from my main tank into the larval tank, probably about 80% water changes at this point.
Days 6-8 - On these days I continued larger water changes to keep the Ammonia level down, keeping it at or below .25, but still kept having a good bit of mortality, and I noticed something funny about some of the dead larvae. They were pink. For some reason some of the larvae that died and ended up in the bottom of the tank had pink spreading out from them on the tank bottom. (More on this later).
Days 9-10 - By Day 9 I only had about 7 left, and I kept a good eye on water chemistry, feeding less, and doing less water changing, as it wasn't necessary, but on Day 10 I only had two larvae left, and on D11 I had none. So batch #2 was down.

Larvae Batch #3
On 11/3 my third clutch of eggs hatched. For this batch, my L-type rotifer culture was really depleted, and the little bit of S/SS-type I managed to save from my first wasn't large enough yet to be depleted for feeding either. I decided to try feeding the frozen rotifers, which were Branchionus spp., just like my cultures, because I thought the larvae were eating the frozen along with the live in Batch #2.
Day 1 - At hatch, the larvae, which appeared to be about 250+ this time, were transferred to the larval tank (AGA 5.5, blacked out sides) with the same heater/foam filter as Batch #2, but I decided to raise the temp a bit, to 77-78F. Some time over the course of the first 24h, I noticed what I think may be the cause for some of the larvae to die and possibly cause the pink decay on some of the dead. They appeared to be attempting to eat the foam filter! I noticed some would make "jabs" at it, and back away twitching like they were trying to take bites out of the bright yellow foam ring. I really think they were nipping at it and trying to tear pieces of the foam away. I think this may be why some of them died and have a bright pink area around them on the bottom glass. Could this be the foam they swallowed being broken down?
Day 2-3 - I removed the foam filter, and replaced it with just a airstone, set to make small bubbles, and set fairly low also. I made water changes daily, about 50% a day to keep the Ammonia as low as possible, but by the end of Day 3, I had 100% mortality again. To note the Ammonia level, without the foam filter in there, it kept rising, so it stayed around .5, even after doing massive water changes, probably due to the use of frozen rotifers as food.

Larvae Batch #4
So on 11/6, my male had a new batch of eggs in his mouth again. I am currently awaiting this batch, but would like to get some advice here so maybe I can finally succeed in bringing a clutch to meta, and hopefully have some juveniles to give some of my friends. What do you guys think?
(1) Are SS/S or L-type rotifers good food for this species? I am not so sure they are. Has anyone done a gut dissection to see if rotifers are there?
(2) Why would they die and then some have what looks like hot pink blobs around them when decaying (keep in mind its just some, not all)? I think its the ones eating the sponge filter that look like this.
(3) What about the temp for the larval tank? I think 75F might have been a bit low, so I am thinking 78F is a better setting, more reflective of the Caribbean temperatures this species is used to.
(4) What are acceptable Ammonia levels for larval tanks?
(5) Are 50%-80% Water Changes to much? Even when the replacement water comes from the main tank to keep with chemistry, and is trickled in over the course of 1-2hrs?
(6) Would a bigger tank be better?
(7) Should I try to get Acartia tonsa copepods as a food source?
(8) How much should I "bubble" the larval tank? I read large bubbles were bad, so I tried to use a smaller airstone, with smaller bubbles, and on a low setting.


Any inputs are welcome, plus any information on successful breeding attempts in this species would be greatly appreciated.
Sorry for such a massive post! I just wanted to be thorough :)
Landon
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby Amie » Sun Nov 08, 2009 12:24 pm

Excellent post, I am glad that you were willing to share your experiences here.

It's great that you have taken the time to get both species of rotifers, but are you culturing them? Or are you keeping them in the fridge, pulling them out and then feeding them to the fry? What are you feeding the rotifers? Rotifers should be thought of as an empty shell that delivers their last meal to whatever eats them. So if the rotifers are starving, the larvae are also starving. The weaker larvae that die first, possibly had smaller yolk sacs, so they starved first.

I don't think that the fry could be strong enough to pull the sponge from the filter. But there are probably dead rotifers on the filter that they are picking at.

I would stop being so concerned about the water changes, and concentrate on getting the larvae well fed. Siphoning the bottom of the tanks is okay, but a water change everyday is not as important as the food. Your ammonia levels are increasing because of die-off from both the larvae and the rotifers. Eliminate this, and you won't need to worry about the water quality as much.
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby llasseter » Sun Nov 08, 2009 2:12 pm

Hey Amie,
The first culture of rotifers, used for Batch #1, I picked up from another breeder, they were kept in the fridge to slow down metabolism, because I didn't have enough phyto to feed them. I have been culturing the second culture I picked up, but the culture was less than a gallon, so I had to supplement feeding with frozen also for Batch #2. I know about the low nutritional value of rotifers, so I have been feeding them either a mix of phyto (like DT's), or Nanno. Right now I have a small culture of S/SS that a I salvaged from the first culture going, and I am keeping the second culture of L-type going also. I am still really wondering if rotifers are a good food source, for Tengels success here, he used A. tonsa, and Moe succeeded with wild caught Florida-keys zooplankton, mentioning there were not rotifers in gut checks. Thanks for the response!
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby Amie » Mon Nov 09, 2009 1:23 am

I would still gutt load the rotifers with something like super selco, if I were you. Since I've never raised jawfish, I certainly wouldn't know what food to start them out on, but you are right, rotifers are never the greatest food source. If the larvae are big enough to eat A. tonsa or another kind of copepod, then you are wasting your time with rotifers. Sorry I can't be more help. If you need a start of copepods (Tigriopus californicus), I'm always happy to send some for the cost of shipping. I've raised clownfish on copepod larvae without using rotifers or brine shrimp. I didn't have to enrich them, which was really nice.
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby llasseter » Mon Nov 09, 2009 5:57 am

double post.. see below
Last edited by llasseter on Mon Nov 09, 2009 6:06 am, edited 1 time in total.
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby llasseter » Mon Nov 09, 2009 6:06 am

What size is larvae in this particular species? I really need to do a gut check in the next batch. If they can fit a copepod in their mouth, then surely they have to eat the rotifers also I would think. Wouldn't it just be easier if everything could fit bbs in their mouth :)
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby Tengels » Mon Nov 09, 2009 7:58 pm

I'm pretty sure small rotifers can do the trick (you proved it yourself since you had larvae on this food at least for several days), but copepods are a better choice.(nutrition is better and it's much more easy to maintain water quality )I used tonsa naupli sized 100-200 mic , small rotiers are up to 180 mic depending on salinity and specie.I think L-type may be to big day 1,2,3 and maybe 4.
I think larvae of jaw-fish is much more sensitive to water quality than clownfish f.example , and they tolerate larger water - changes (50 % a day) way better than bad water quality.Bigger tanks , more food.The higher the temperature , the faster development , but even bakteria grow faster and rotifer grow and dies faster.
Thomas
Last edited by Tengels on Tue Nov 10, 2009 7:30 pm, edited 1 time in total.
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby llasseter » Tue Nov 10, 2009 12:33 pm

Tengels,
My Batch #2 that went to 10 days was done using a mix of frozen rotifers, which may have had some S strain in it, and live L-type rotifers. But I must mention, by day 7 the survival rate for the total spawn was less than 10%, Day 8 probably only 10 larvae left, Day 9 there were only maybe 2 or 3 larvae left, Day 10 there were none. So I wouldn't really call it much success. Hopefully I can get the S-type culture up large enough and enrich them enough to get decent success rates this time.
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Re: Pearly/Yellowheaded Jawfish - Larvae batch #4

Postby Tengels » Tue Nov 10, 2009 7:42 pm

Can't see you mentioned any use of phyto in the larvae tank.This would help maintaining density and nutrition value of rots , and will do good for water quality.
Don't mind to much in mortility % , my "best" batch was the one with the largest % , they almost died all after during yhe first 2-3 days ,after that there was no losses at all
good luck
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