pygmy angelfish larvae

[david willmore]

Folks,

I am new to this forum, but am trying to rear larvae of the centrophyge angelfish. Although several people have raised them through metamorphosis, they appear to have used size sorted wild plankton as larval food. Unfortunately I do not live on the ocean, and need to cultivate rotifers, ciliates or copepod larvae and pack them with HUFA's before feeding. But these methods have not resulted in larval survival for more than about 12 days. Does anyone have any other first food suggestions?

Thanks,
Dave Willmore

 

[FMarini]

David:
i'll jump in first.
Centropyge angels have been reared successfully by a few groups and has you have correctly ID its the first food which is the key. It is unclear what exactly are the first foods. I say this becuz the groups which have successfully reared these fish are keeping their secret reciepe secret. Frank Baensch recently published in both Seascope and in FAMA (or TFH-I don't recall which ones) that he was successful and in both articles he purposefully omits what he fed the fry -stating he'll publish the results first. The group from waikki also published a splashy news bite which stated they found the "natural" food and were both capturing it and culturing it.
Okay MY guess would be its some sort of copepod larvae are most likely the first foods, and for enrichment of the copepods its hard to say what is missing. But Yes HUFAs are prolly paramount, but there are possibly a number of other things which influence survival.

Are you saying that you have been successful at raising ciliates and feeding both ciliates and greenwater to your copepods to produce viable copepod larve and these are still not enough?
As for other first foods; you can try totally artifical like golden pearls, or another live food would be oyster viligers as mentioned in Martin's recent column, as these might be small enough.
So w/ that said, your statement intrigues me. You state that your fry reach day 12 before dying, are you saying they all die eariler -like a massive die off at day 3-5(suggesting the fry are not eating at all) or if they are dying at a later time point, which suggests that the first food is not nutritious enough to sustain them.
I have a few more guesses, but I'll let Martin jump in
frank

 

[Martin Moe]

David,
Interesting post. I worked with Centropyge for some months a few years ago, the flame and the cherb fish, and my survival results were about like yours, maybe a day or two shorter suvival, and I was using wild plankton seived down to the 20 to 50 micron range. Only a few copepod napuli were in that fraction. I think with wild plankton and these very small larvae you have to be careful as to where and when (tides) the sample is taken to make sure that you get a good representation of the offshore larvae that contains more of the smaller organisms, or at least has them in a less dense medium that allows them to be collected alive. Now if you have survival to 12 days, that's not bad, it shows that the larvae are getting some nourishment. I would continue on with that regimen, at least for a while yet, and see what you can do to improve the chemical environment of the rearing water. Also perhaps experiment with various ways of enriching the rotifers, perhaps do some larval dissection to make sure that the larvae are feeding on the rotifers, perhaps seive the rotifers down just before feeding with an 53 to 10 micron seive to select the smallest size. It may also be well worth while to experiment with cilliates, see my article in AA and also Frank's recent articles on larval food. Lots of good information there. There are other possibilities for tiny food organims, particularly the larvae of bivalves and echinoderms, that can be provided by land locked aquarists, but these do require a rather large investment in technology and structure that most aquarists don't have the time, space or money to attempt. Probably cilliates and rotifers, properly enriched are your best bet at this point. Perhap even a marine "infusoria" culture might be acceptable if you can control the negative elements )fungus and bacteria) in such a culture.

Now that Frank (and Karen and Charles L.) have broken the "four minute mile" and showed that, "Yes it can be done." I think we will see some other successes soon, but it will be more difficult than clowns. Incidently if you haven't yet reared clownfish, I would suggest that you do so, for the hands on experience of rearing marine fish provides insights that cannot be acquired in any other way.

Martin

 

[david willmore]

Frank and Martin,

Thanks for the replies. I'd also guess that the folks at Waikkiki are using copepod larvae. If wild collected, they are probably high enough in lipids that HUFA enrichment is not necessary. Yes I've fed diatoms, greenwater and also infusoria collected directly out of my tanks, but I haven't isolated any specific ciliates for monoculture. Instead, I've used the "shotgun" method, throwing things at the larvae from all over the place.

Frank, I haven't tried golden pearls, but will look them up and hope they are in the 20-30 micron range, and hope that a non-living food will move in the water column well enough to entice larvae to strike. I live near enough to the Chesapeake Bay that I could also try local oysters, inducing them to spawn is widely reported in the aquaculture literature. But there have been a lot of disease in the Chesapeake Bay oyster population and I think some of them add toxins to the water. Nevertheless, a big table of water and a couple of bushels of oysters isn't much to waste on an experiment.

Martin, I'll try to isolate and culture specific ciliates using the vegetable juice method you've described. Perhaps the ciliate density was lacking, no surprise because my ciliate cultures are very hit and miss. Regarding the marine "infusoria" culture, I would guess that exposure to sunlight or other low level U/V source will tend to keep fungus and bacteria in check.

We are really talking about two problems here, the smaller problem being an acceptable first prey and the larger problem being the nutritional value of the prey. If the fry eat rotifers but do not survive on them, does this indicate a mineral absorbtion problem as the larvae change from silicated diatoms to the rotifers? Is that the reason that bivalves are fed diatoms instead of green or blue microalgae? Which echinoderms are candidates for spawning?

Dave

 

[FMarini]

Dave:
you've identifed the salient points. These are 2 different and yet critical points in feeding. One is the first prey item and second to properly and sufficienctly enrich this food item to ensure fry survival.
We have to wait until frank Baensch and company release their magic formula for sucess w/ centropyge angels. Maybe Martin has more info.

Golden pearls come in a few grinds one of them is around that size. They certainyl don't move in the water column like a rotifer or copepd larve, however a few mariculutre facilities have reported (what I would call minimal) success w/ this product as a first food-survival rates are low but better than what you've reported. Its an incredibly nutritionaly dense food, so much so that you have to ensure water quality as it will foul small volume quickly.

Which echinoderms are candidates for spawning?

seaurchins mainly, very easy to get to spawn and release tons of gamates.
frank

 

[Louis Z]

I know I am late to the discussion but which copepods have you tried? Any specific ones or are they ones you have isolated from the aquariums? The size of the copepod larvae needed depends on the mouth size of the fish larvae. Is it possible that you may not be using the properly sized larvae? Or could it be that the larvae do not maintain themselves in the water column with the fish larvae. And as to what microalgaes are you using to enrich the copepods. As for the rotifers like moe stated you have to find the right sized ones. There do exist many rotifer species and they do vary in size - some large and some small. Also with which algae sp do you use to enrich and do you use the selco or selcon? Another thing to point out is that some fish larvae may injest the rotifers but are unable to digest them and pass thru the digestive system whole. The Question I have for Martin Moe is wouldnt live microalgae be sufficient to culture cilates and be a better way to enrich than the vegetable juice? I realize the V8 may be easier to use but could the final enrichment be with microalgae just as rotifers are fortified after being on a yeast diet? The other idea that I had concerned the ciliates and selco itself. Could the ciliates be enriched or raised on selco only?

 

[Louis Z]

David , when does the majority of the angelfish larvae die off? Does the majority of the larvae die at day 12? And has any of the larvae exceeded day 12? If you did nothing to feed the larvae how many days would it take for the larvae to die? What type of diet do you have the spawning pair on? And what is your larval setup like?

 

[Martin Moe]

Louis, I can't answer for David, of course, but I'll toss in my opinions and what I know from what I've done with this group. I would guess, if David's experience is similar to my own, that the last of the larvae dies on day 12 and that most of the mortality occurs before day 9. Evidently a few of larvae are able to obtain enough nourshment to "hang in there" for a few days after starvation decimates the majority of the spawn. Centropyge begin feeding after the organ systems and eyes complete development at about 3 to 4 days after the egg hatches. Cold water delays development and warm water speeds it up. There is enough nourishment remaining in the vestiges of theyolk sac and in the oil globule (the last of the egg's nourishment to be absorbed, (hmm.. it would be interesting to investigate the composition of the egg's oil globule and exactly what this adds to the development of the larval fish). The larvae are sustained (variablely) on the yolk sac for a few days after feeding should begin. However, the larvae are so small, and develop so quickly, that if feeding does not begin and/or is not adequate, they pass the point of no return within probalby a day or two. Without any food at all they do not live more than day 6, and even if enough food is injested to keep them alive for a few more days, growth and development is so compromised that survivial is extended for only a few more days, at best. From my experience with the larger Pomacantus angels, a strong well fed larve has grown extensively by day 12. A doomed larvae at day 12 looks much as it did at day 6. But still getting the larvae, even only a few, to day 12 is a strong indication that one is on the right track.

As you pointed out in your second message, there are many questions yet to be answered in culture of these small egged pelagic spawners. As to the microalgae vs vegetable juice culture of rotifers and cillates, I'm sure that a good culture of microalgae is superior to vegetable juice in the nutrition that is eventually delivered to the fish larvae. However the greater ease in maintaining cultures and the potential of enriching the cultures gives, in my opinion and experience, a place in home based culture work for vegetable juice based cultures. Where cost is not a problem, then some of the commercial microalgae preparations now available would be much better than vegatable based cultures. Also what is accepable to culture clownfish, gobies and dottybacks, may fall far short of what is necessary for angelfish.

Martin

 

[Louis Z]

Thanks Martin for input to my questions. I have started to work with the Instant Algae by reed mariculture which is a concentrated dead intact nanno liquid that is stored in the fridge and lasts up to 3 months. Very simple to use but I dont know other that what randy reed states on the sucessfullness of his product. I realize that it grows rotifers and maintains Brine shrimp yet does it adequately enrich the prey enough to translate into survival of first feeding larvae? I dont have larvae to try it out on so I have to wait and see. The nice experiment would be to feed some with live nanno and others with the Instant Algae. He also has other combinations of his algae to feed and maintain copepod populations. Again this would be nice to use but the question arises of how well the copepods are enriched. I agree that maintaining the algal cultures are a time consuming aspect especially if 3 or 4 strains are worked with. Thats why I am looking for the Instants. Drawback of them is short shelf life(3 months) and a large bottle that I would never use completely and see it as a waste. Although if the end result is positive the price is insignificant. The one last thing I would ask is if ciliates are used how long do the larvae last? I am asking if you ever tried without rotifers and seen results with ciliates only. Or did you feed rotifers off the bat and hope the ciliates would be there? Because if the larvae are extended by several days by the ciliates then I would think worth culturing, yet if they die as at the same time of unfed larvae then whats the point. I understand that one ciliate may not be the answer. I would think that a ciliate with slowmovements and less extended large cilia would be ideal for the prey to swallow. Also I presume that the ciliates would be preferred in the initial days after yolk absorption and would be less beneficial as the expenditure of energy outweighs the amt of nutrition these ciliates would have. There is an abstract that I located on fishlarvae.com that brings up the term Naked Ciliate. I cant say that their hypothesis is sound but the idea of a naked ciliate sounds like they would be ideal for fish to consume. Ill stop now for I am beginning to ramble on. Thanks again, Louis.

 

[delbeek]

I am not sure how many times I have stated this but I guess it bears repeating once again after reading the posts in this thread: the Waikiki Aquarium did NOT use copepods as a first food to rear Genicanthus, they were used LATER in the rearing cycle. We used an organism that was cultured ... NO wild plankton tows were ever done to obtain food to rear these fish. That is why we consider what was done here a somewhat greater achievement; we used CULTURED foods exclusively. Frank Baensch and The Oceanic Institute used wild plankton tows and copepods to rear their Centropyge.

Aloha!
JCD

 

[Louis Z]

Hi JCD, Can you update me/us on the progress of the genicanthus rearing? Were you able to repeat the process? Or have a higher success rate? The last update from what I had seen was in May. Just hoping that things are going well. I did have another question- When an Aquarium rears fish, can they be sold to private individuals or are they usually shared/sold amongst other Aquarium institutions?

 

[delbeek]

Louis: The adults stopped spawning for a while but have started again now ... Karen is starting new runs. Once she is successful again and is sure of her techniques she will publish them.

Aloha!
JCD

 

[delbeek]

Louis: Karen said to email her and she can answer your questions: [email protected]

I am curious ... what fish have you successfully reared?

Aloha!
JCD

 

[Louis Z]

Thanks JCD, I'll email her. As for which SW fish I have bred - None. I really just started keeping a saltwater tank in June of this year. I have set up a 29gal FOWLR to house 3 pep.shrimp and a symbiotic pair(Amblyeleotris randalli /shrimp). I just recently acquired more specimens of the Randalls goby. I lost 2 fish (one didnt eat and seemed emaciated) and the other jumped. I kicked myself for that one and lowered the water levels and now have saran wrap as a top. I did just introduce two of the gobies together today and it remains to be seen if successful but pairing looks positive vs other trials. I also have acquired 3 specimens of another goby sp. that I have not found an ID for. Hopefully these provide me with something to work with.

 

[delbeek]

Louis: You probably don't want to hear this but Karen always tells people who have no experience in raising marines to begin with clownfish. They are amongst the easiest to rear and the techniques and skills you will learn and gain from raising them are similar for other fish. Begin with clownfish and hone your skills then tackle other, more difficult species.

I would not use saran wrap, cuts down on gas exchange to much, try window screening or some other mesh-like material instead.

Aloha!
JCD

 

[delbeek]

As an example of the above Frank Baensch setup his hatchery and began with clownfish, then dottybacks and gobies, and now works mainly with Centropyge ... a 2-4 year progression.

Aloha!
JCD

 

[Louis Z]

Thanks JCD any advice is appreciated. I knew I was skipping a lot of steps when I started choosing gobies to work with. But I was hoping to learn along the way. I am limited by space and cash now. I cant spend anymore cash on any other species so I have to make do with what I have. I am also tied up with tanks- I cant set up any more and the goby species do well in a 20 and 10gal. I have resorted to using large plastic bin containers for my live food cultures. Yeah I should have started with clowns but went with my heart and found the cool gobies that would keep my intrest. Clowns are nice yet didnt attract me as much.

 

[Louis Z]

two links. first http://oceanicinstitute.org/news&info/0 ... lfish.html and http://oceanicinstitute.org/research/ai ... oming.html