CORYDORAS ROBINEAE - My successful hormonal spawning

[cartouche]

Although I know that some visitors of this web site don't like hormonal breeding of fish, I would like to share my experience with the hormonal breeding of Corydoras robineae - because in the end, it brought the same problems I mentioned previously in other "problematic" species.

I have tried to breed this species unsuccessfully for about 5 years. I used different groups of fish, tried various "tricks", including an imitation of the "dry" and the "rainy" season (a stupid experiment, during which I once lost 2 pieces of Corydoras tukano) - but the fish didn't react at all. In 2006 I eventually decided to breed them hormonally with carp pituitary. My patience was really over after I had got an email from Eric Bodrock, "a successful breeder of Corydoras robineae", who plainly stated that after his three accidental successful spawnings he had never had any success anymore and eventually got rid of the whole group "because they occupied too much place in his tanks".

I hoped that with hormones I would be eventually successful, but again, my attempts desperately failed. Although the fish were apparently active after the injection, they produced no eggs. I was wondering why. I stubbornly continued with the attempts for about one year, but considering that then I had little experience with the application, I lost quite a lot of fish, which only increased the degree of my frustration. But paradoxically, it eventually enabled me to solve this mystery. I routinely observed that the dead females had no ripe eggs. And mostly no eggs at all. And this didn't concern only robineae - I saw it in schwartzi, reticulatus and sodalis as well. Irrespectively of how well and how much I fed the fish, they didn't show signs of any filling. I still remember a female of Corydoras schwartzi that eventually seemed to be filled with eggs. I injected it and it unluckily died. I investigated its body and found out that it had only ONE egg!!!

After I eventually mastered hormonal breeding and I started to breed several easier species like e.g. napoensis regularly, I had virtually no useable group of the more difficult species anymore, so I gave it up. But only temporarily. My routine success with the easier species convinced me that I should try it once more. Hence I bought a new, young group of Corydoras robineae and after several months in my tank, I injected them with pituitary. To my huge relief, they really spawned! I couldn't believe my eyes, when I collected 26 eggs from the sides of the tank in the morning. Out of this number, I got 14 juveniles that easily hatched and developed in my soft (8,5 dGH), slightly alcalic (pH 7,5) tap water. After 14 days, they seemed enough big to be placed in a bigger tank with somewhat older sterbai. Unfortunately, from some unknown reason, they didn't bear it well and gradually all died. I really didn't observed any fast growth (as some authors claim). To the contrary, they throve very badly and grew very slowly - at least in the company of other Corydoras.

I was naturally very disturbed by this experience, but I had hoped that I would spawn them successfully again. From the second spawning I got 6 eggs and 2 juveniles, but I didn't bother with them, hoping that I would get much more from a third spawning, only if I prolong the pause between spawnings and give them enough good food. Unfortunately, the third attempt was unsuccessful. And a fourth one as well. As well as a fifth one.

I observed the same thing like previously in my old fish: The fish were active, but produced no eggs. The females simply stayed thin, with no signs of eggs in the belly. Now I understood the cause of my success: The young fish were loaded with eggs from nature, and after I "emptied" them completely, they didn't create any new eggs anymore. I now feed them with bloodworms, cyclops, beef heart, earthworm powder and (about one week in total every month) with tubifex, but nothing changes. At the same time, the easier species like e.g. napoensis or Venezuela black do well on this food and fill with eggs rapidly.

So, I ended with the same problem like before - I can stimulate the fish, but I don't know, how to fill them with eggs. It really seems to be a mystery. Do they lack some food that they have in nature? Or should I simply feed them for many months only with the best food like e.g. Tubifex? Here it becomes problematic, because the prices of tubifex increased markedly during the recent years, and if I fed them with it every day for, say, one year, the breeding may not have been especially gainful.

Any suggestions, opinions?

[Coryologist]

Personally, after reading your post, I failed to see the "successful" part of the story. Additionally, if you can't spawn Corys without resorting to hormonal injections, I'd find another type of fish to work with.

Granted, I cannot claim the large numbers of Cory species spawned (48 in 8 years) as some of the masters, but the only techniques I employ are clean water, good food, patience and a firm belief in Mother Nature. I have waited years for some species to spawn, before having success. Heck, I have never used a spawning mop to collect a single egg, in my life. Perhaps if I did so I would have many more species that I could lay claim to, but my simplistic attitude is, how many spawning mops are there in the Amazon river system? Java moss and/or broad-leafed plants work just fine.

Like I said, just my personal opinion.

Be honest, now. Wasn't a part of the reason for this post simply an attempt to ruffle the feathers of a few people whom you know to highly disapprove of your techniques???

Frank

[cartouche]

Successful breeding is not a success? I could save two last robineae, who survived the first wave of dying, and send you a photo. But I really didn't want to bother with two pieces of this fish, because I had hoped that I would have another ones from future spawnings. Which I don't have. And I don't know, why the fish don't fill with eggs. That's a fundamental problem. I want to breed this species more or less regularly. One successful breeding in a life is really worthless.

[apistomaster]

While successful breeding of Corydoras robinae are not common it has been done many times and none of the documented spawns involved the use of hormones. I think continued patience and using standard Corydoras breeding techniques will work for you. Some fish are just more challenging than others and C. robinae certainly is one of these.

If hormones could be used to successfully breed Symphysodon discus Heckel I would not be averse to trying it. Any technique that allowed me to get a tank bred group of heckel Discus to raise their entire life in captivity may be the key to finally establish an aquarium strain of this species. Altum Angelfish are another species that has been highly resistant to efforts to breed them in captivity. With these two species we are running out of options for inducing purebreds. Some have had better luck crossing male Heckels with wild Blue or domestic females but that is of no use for establishing pure aquarium blood lines. In both species the hurdle seems to be inducing ovulation among the females since the males so readily hybridize with related species.

[Coryologist]

Successful breeding is not a success?

Nope. Not when it's accomplished through manipulation of of the natural spawning process. Not where I come from.

I could save two last robineae, who survived the first wave of dying, and send you a photo.

I don't dispute that you raised 2 fry. I dispute your use of the term "successful" spawning. I see nothing successful in your actions.

But I really didn't want to bother with two pieces of this fish, because I had hoped that I would have another ones from future spawnings. Which I don't have. And I don't know, why the fish don't fill with eggs. That's a fundamental problem. I want to breed this species more or less regularly.

I maintain that you are simply impatient and unwilling to let nature take it's course. I happen to know a very successful breeder who is currently maintaining 2 females of the specie that are bursting with roe. While that does not guarantee any future spawning, it shows that with proper conditioning and a lot of patience, the problem you describe is limited to your fish and the way you keep them. Don't blame the fish for your lack of skill in conditioning them, properly - regardless oh how long that might take. You seem much more interested in manipulating the natural process, than anything else.

One successful breeding in a life is really worthless.

Really? I have many specie of Cory that if I were to spawn, just once, I would be considered it a major accomplishment in my life. If they never spawned again, it would in no way diminish the achievement, nor the personal sense of accomplishment that I would feel. Were I to achieve the results using your methods, quite honestly, I would not feel any sense of accomplishment at all.

I guess if you are in the hobby to make money - your attempts make economic sense. In my case, money does not enter into the equation, so even if you were to develop a technique that I were able to duplicate - I would still choose not to use it. I care more about the personal accomplishment of spawning a "difficult" specie of fish than I do their potential for financial gain.

BTW - why would you expend such time and energy on a $5 fish? If you were attempting your techniques on a $75 Cory, although I would still have personal disdain for your techniques, I would see the economic viability of your actions. No - wait. If you were successful in your attempts in that scenario, all you will have ultimately accomplished is taking a $75 fish and raising them in quantities that would reduce them to being just another $5 Cory. I fail to see any "upside" to your attempts to spawn fish through artificial means.

That being said, as they say, everyone is entitled to their personal opinion and it truly does take all kinds, to make the world go 'round. - Frank

[cartouche]

Eric Bodrock also had "patience", but he has never spawned his Robineae again and later got rid of them. And if I didn't use hormones and I followed your advice, I would unsuccessfully try to spawn them perhaps until my retirement age, not knowing, where the real problem lies.

And by the way, Robineae is quite an expensive fish. At least in my part of the world.

[Coryologist]

Eric Bodrock also had "patience", but he has never spawned his Robineae again and later got rid of them.

Two points.

1. Besides being a respected seller, Eric is heavily involved in his club's Breeder Award Program and I can understand moving fish along that aren't producing, both from a "points" and a financial standpoint.

2. How do we know that if he had kept them another day, week, month or year - that they would not have spawned for him? We don't. Do we know if his females ever became gravid?

And if I didn't use hormones and I followed your advice, I would unsuccessfully try to spawn them perhaps until my retirement age, not knowing, where the real problem lies.

So - are you saying that you now know where the problem lies, or is the problem still a mystery?

And by the way, Robineae is quite an expensive fish. At least in my part of the world.

I do not dispute that, however it truly is a $5 fish, here.

http://www.aquabid.com/cgi-bin/auction/ ... 1233415726

When I acquired my first group of CW016's, I waited over a year for them to spawn. Had I given up in frustration in a few weeks or months, I could not lay claim to being the first to ever document their spawning. To me a year is nothing to wait for a fish to spawn. I have a group of C. condiscipulus I have had for close to 8 years. Not a single egg that I have seen, to date. Some morning, I'm going to turn on the lights and there will be eggs. Not when I'm ready, but when they're ready. And - if they never spawn, it doesn't matter to me, because every day I am blessed to have the opportunity to enjoy their natural beauty. That is good enough reason, for me, to own almost any fish.

I think the difference in our approach can best be summed up, thusly: Some people spawn fish, to sell them. I sell fish, because they have spawned.

Honestly, isn't just having the opportunity to enjoy the beauty of this fish every day, for many years, enough reason to keep them, whether they spawn or not???



I think so, but like I said - to each his own.

Frank

[apistomaster]

I breed for both personal satisfaction of the accomplishment and profit whenever possible.
No where is it written that one is guaranteed success with some of the more difficult fish but Corydoras robinae is not among the most difficult of all tropical fish to breed. They are a worthy challenge but certainly doable.
I only took on the challenge of breeding some of the Hypancistrus spp and Peckoltia sp L134 in 2006 but I finally managed to breed L260 and L134 last year and I was close to giving up. I'm glad I didn't give up on the L134 since they produced nearly 180 fry over a six month period. They have stopped and I suspect they spawn seasonally. I now know that these fish take longer to reach maturity than I would have first estimated: 3 to 3-1/2 years appears to be how long they take to reach sexual maturity.
If the Corydoras robinae are not showing signs of ripening ova then consider the possibility that they may take longer than you expected for them to reach sexual maturity and the possibility that they may be seasonal breeders. I would suggest that you continue to work with them for five years and meanwhile continue breeding those species that produce enough to be commercially viable.
Every good fish breeder should have a few species that present them with an extraordinary challenge to cultivate some humility.

[Coryman]

Being totally against spawning inducement by the use of hormone injection, especially when you consider the action is the equivalent of you having a sharpened scaffold pole stuck into your body.

If it were the last specimens know to exist on the planet then I may relent, but the fish you are very successfully killing by this method is not so far as I know endangered.

Something you may or may not know about female fishes is that there are more than one hormone involved in the process of reproduction and a little research would have enlightened you to this fact. First of all there is a hormone that tells/triggers the fish to produce and a totally different one that stimulates the spawning. Both of these hormones can be stimulated naturally, nature has been doing it for thousands of years and funnily enough without the aid of a hypodermic needle.

For you to have fishes that do not produce eggs at all I would put down to lack of basic aquarium skills, my group of 6 C. robiniae are as close as it gets to breeding as they can be without actually spawning, with both females in the group definitely full of eggs. As yet I have made not attempt to trigger them, but I will be in the near future.

Ian

[apistomaster]

In commercial and governmental fisheries hatcheries that use hormones on the breeders many of the fish are stripped and artificially inseminated with mostly fatal results on the breeding stock.

[cartouche]

For you to have fishes that do not produce eggs at all I would put down to lack of basic aquarium skills, my group of 6 C. robiniae are as close as it gets to breeding as they can be without actually spawning, with both females in the group definitely full of eggs. As yet I have made not attempt to trigger them, but I will be in the near future.

Ian

Oh, thank you! After 13 years of breeding Corydoras and spawning 15 Corydoras species I still lack some basic skills! It really wouldn't occur to me!

Isn't it strange that this happens only with the problematic species that nobody is able to breed regularly - robineae, schwartzi, sodalis, reticulatus? Maybe I know even better than you, what Corydoras need for egg production (an optimal ratio of certain essential fatty acids in food). The best food for this purpose are earthworms; then there is a large gap and on its end you will find tubifex and beef heart. All other types of fish food are not worth noting (perhaps only except some marine crustaceans).

I could feed them with tubifex every day for the whole year, but it would cost me so much money that it wouldn't be reasonable. And I could probably feed them with earthworms for the whole year, if I lived in rainy England. And I can feed them with beef heart, but unfortunately, they simply don't like it too much.

I had similar problems with Corydoras loxozonus, who didn't spawn even after hormonal injections (actually only once they gave me 2 infertile eggs) After 18 months, I thought over selling them. Curiously, they suddenly started to spawn on their own and produced 60-110 eggs from each spawning. And what is even more curious, I didn't make any significant changes in the diet. No earthworms, no tubifex. So where is the problem?

[cartouche]

If it were the last specimens know to exist on the planet then I may relent, but the fish you are very successfully killing by this method is not so far as I know endangered.

Ian

During the last two years I have made several hundreds of hormonal applications and I have lost only one male of Corydoras napoensis - my best male, by the way, that I was really very sorry for. During the last 17 months, I have lost none. It is really not so dangerous, if you know, how to do it. The first attempts were painful, but I had no other possibility, because no breeder will betray his secrets.

[cartouche]

If the Corydoras robinae are not showing signs of ripening ova then consider the possibility that they may take longer than you expected for them to reach sexual maturity and the possibility that they may be seasonal breeders. I would suggest that you continue to work with them for five years and meanwhile continue breeding those species that produce enough to be commercially viable.
Every good fish breeder should have a few species that present them with an extraordinary challenge to cultivate some humility.

I had very mature Schwartzi, Sodalis, and Reticulatus imported from South America, I have tried to spawn them for 4-5 years, but with zero success. They really didn't produce any eggs.

[Coryologist]

because no breeder will betray his secrets.

That's nonsense, There's not a person here who would not tell you everything they know about spawning Corys, although I don't think you are very interested in hearing what others have to contribute. If I may let you in on a little secret? There are no secrets and that the absolute truth. I am constantly accused of "holding back" information that might help others. The truth is - I don't actually know very much and I certainly do not possess a single secret. I am happy to share my very limited and narrowly focused knowledge, with anyone, at anytime. I maintain that all I do is keep the fish healthy and properly conditioned for spawning. I do not even attempt to "trigger" them in anyway. Just normal water changes. That's it. You know - sometimes less, actually is more. If I had to work that hard to spawn fish, I'd find another hobby.

Put away your syringe. You are wasting your time.

Frank

[Jools]

Wasn't a part of the reason for this post simply an attempt to ruffle the feathers of a few people whom you know to highly disapprove of your techniques???

Maybe so, in which case just don't answer - I've found from a little bit of experience in running this forum that's the only viable solution. If you can read past the methods, and many will not, is the question, however, how to get females of certain Corys gravid?

I am not convinced anyone is listening. I am not convinced anyone is interested in helping cartouche. So, I'll keep an eye on the post and lock it if we get any more mudslinging in either direction.

Jools

[Jools]

because no breeder will betray his secrets.

That's nonsense

I think, read in context, that means any syringe wielding breeder, as opposed to those that do it the hard way.

I am quite sure most of the syringe users keep their secrets - not surprising when you see the reaction to their activities.

Jools

[Coryman]

I am not convinced anyone is listening. I am not convinced anyone is interested in helping cartouche. So, I'll keep an eye on the post and lock it if we get any more mudslinging in either direction.

Jools.
In many previous topics by cartouche I passed on and offered information based on my own personal experience, but all suggestions and tips were rebuked. When asked a question what comes back is invariably negative and without any real information.

in which case just don't answer

As ever you are 100% right and I will as of this post "Butt out" from further public debate with said member.

All.
Every one that knows me knows I am 100% free with information with what I do with Corys and hold nothing back. To date I have successfully spawned 106 species of Cory. Some are easy some are not, but having said that what's easy to me may be hard for someone else and visa-versa, this can be down to a wide variety of factors. I do not breed for financial gain and never have done, so the need to produce continuous batches of the same species has never been on my agenda. Other than the injection issue, this is where we differ and I have no issues with anyone trying to may or supplement an income from breeding their fish, it all makes world go round I suppose. I made the comment about "Basic aquarium skills" perhaps I should have re-phrased it and said "Basic development skills" as like in many aspects of life if it don't work, change/alter things and keep experimenting until you get a result. It can be a long slow process. There are basic rules of development and if not followed it can be impossible to know what was the wright move and what was not.

Ian

[paul dixon]

Guys, I have just read through this thread and it seems to me that we have to move on! Life is just too short and wonderful to waste on fruitless debate.

[Deb]

I thought it was interesting, and worth reading. In some sense every debate can be called fruitless because rarely do the two parties agree at the end.

I enjoyed Frank's insights and thoughtful comments, and tend to agree with him on all points. Ian gets my attention, as usual, with his no-nonsense approach.

Lovely photo by Frank. Worth reading every word just to see it.

[apistomaster]

because no breeder will betray his secrets.

That's nonsense

I think, read in context, that means any syringe wielding breeder, as opposed to those that do it the hard way.

I am quite sure most of the syringe users keep their secrets - not surprising when you see the reaction to their activities.

Jools

I have mainly experimented with injecting metroniadazole when it was only available as Flagyl and have tried other antibiotics. That was 4 decades ago. Much more recently I tried treating small egg layer female tank water with the injectible female human gonadtropic hormone of some sort but that seemed to be a dead end. Some fish are too small to inject without microsurgical microscopes and associated tools.
The methods I used were fairly crude but most wild Discus are good sized fish to work on. If you learn the anatomy of your study fish then aiming to avoid internal organs isn't too hard. Most of the time my goal was to inject the medications to intraperitonelal areas.
I was working with mainly lost cause specimens but despite my crude attempts, I managed to see some fish make good recoveries.
I would imagine trying to inject hormones to the gonads themselves would be complicated and require well equipped lab facilities' access.

[mountainman36]

So this is my first post, but i read the whole thread on the robinae corys.....you two guys really got upset. I know my opinion doesnt count since im a newb, but come on. I have a degree in fisheries biology, i have injected plenty of fishes, mostly with antibiotics, but inducing spawns does have a place. A lot of fishes have become viable comercially after someone "figured them out" with injections. And fisheries biologist have to inject fishes to keep the schedules working, and to increase yields, so it become a viable option to raise hatchery fishes for stocking programs.

Of course it is not a natural way to get them to spawn, and im sure any injector would agree with that, but it doesnt mean it wasnt successful.

If you are breeding fishes for pleasure, then injections may negate that pleasure, but if you are trying to make a few bucks, and your livelyhood depends on it, injections are a great and viable way to go....

Also - many stripped fishes do fine, and are not killed by the process. i have stripped a few koi and striped bass in my day, and they do fine after.

theres my 2 cents.

i look forward to getting some good info here for my garage fish room. I just hope i am not treated rudely by a person that thinks they are superior to me because they dont approve of my methods.

RPC

[JoeO]

So this is my first post, but i read the whole thread on the robinae corys.....you two guys really got upset. I know my opinion doesnt count since im a newb, but come on. I have a degree in fisheries biology, i have injected plenty of fishes, mostly with antibiotics, but inducing spawns does have a place. A lot of fishes have become viable comercially after someone "figured them out" with injections. And fisheries biologist have to inject fishes to keep the schedules working, and to increase yields, so it become a viable option to raise hatchery fishes for stocking programs.

Of course it is not a natural way to get them to spawn, and im sure any injector would agree with that, but it doesnt mean it wasnt successful.

If you are breeding fishes for pleasure, then injections may negate that pleasure, but if you are trying to make a few bucks, and your livelyhood depends on it, injections are a great and viable way to go....

Also - many stripped fishes do fine, and are not killed by the process. i have stripped a few koi and striped bass in my day, and they do fine after.

theres my 2 cents.

i look forward to getting some good info here for my garage fish room. I just hope i am not treated rudely by a person that thinks they are superior to me because they dont approve of my methods.

RPC

What you are talking about has its place in saving species that are endangered. But, in this case, the species is not endangered. So when you inject fish to assist them in spawning, aren't you degrading the species as a whole? Won't this just tend to mathematically reduce the number of fish that are able to spawn normally and replace them with fish that have to be aided by hormonal injections.
Won't your breeding stock eventually never be able to spawn normally?

[apistomaster]

In an earlier post, I mentioned that stripped fish may die. I was thinking about typical aquarium fish not large game or food fish when I wrote that.
The smaller ornamental fish species can not tolerate stripping without getting bruised or worse. These kind of losses may be acceptable if the result is the production of a large number of fry vs none.
Artificial methods will not cause any difficulties in breeding any resulting fish save those that are inherent to the species in question.

[Atlantis Child]

I think hormonal spawning does have a place, like when it's an attempt to stop taking fish from the wild, and start breeding domestically. Clown Loach for example. All of them are taken from the wild, and none have yet to be domestically bred (unless I missed the news?). I'm rather uneasy about taking fish all from the wild for aquariums. Taking more than a few of the (rarer) fish doesn't seem right.

[Noorphish]

Hi,

To breed clown loaches look at this: http://www.aquarium-dietzenbach.de/inde ... %3Dzucht_6

Translate with google into english.

[cartouche]

So this is my first post, but i read the whole thread on the robinae corys.....you two guys really got upset. I know my opinion doesnt count since im a newb, but come on. I have a degree in fisheries biology, i have injected plenty of fishes, mostly with antibiotics, but inducing spawns does have a place. A lot of fishes have become viable comercially after someone "figured them out" with injections. And fisheries biologist have to inject fishes to keep the schedules working, and to increase yields, so it become a viable option to raise hatchery fishes for stocking programs.

Of course it is not a natural way to get them to spawn, and im sure any injector would agree with that, but it doesnt mean it wasnt successful.

If you are breeding fishes for pleasure, then injections may negate that pleasure, but if you are trying to make a few bucks, and your livelyhood depends on it, injections are a great and viable way to go....

Also - many stripped fishes do fine, and are not killed by the process. i have stripped a few koi and striped bass in my day, and they do fine after.

theres my 2 cents.

i look forward to getting some good info here for my garage fish room. I just hope i am not treated rudely by a person that thinks they are superior to me because they dont approve of my methods.

RPC

What you are talking about has its place in saving species that are endangered. But, in this case, the species is not endangered. So when you inject fish to assist them in spawning, aren't you degrading the species as a whole? Won't this just tend to mathematically reduce the number of fish that are able to spawn normally and replace them with fish that have to be aided by hormonal injections.
Won't your breeding stock eventually never be able to spawn normally?

As for "degrading" the fish: I hormonally spawned stubborn Corydoras napoensis, who had refused to spawn for 1,5 year. After 2 hormonal spawnings, the third spawning was spontaneous. Since that time I have spawned them many times hormonally, when I just needed it, because they have a large number of eggs. Recently, I again spawned them 2-times hormonally, with a 1-month pause. Since I already had almost 600 pieces of fry, I didn't want to spawn them again, and I simply let them be. To my surprise, today, after ca. 6 weeks from the last hormonal spawning, they spawned naturally and gave me about 150 eggs.

And as for Corydoras robineae, I am surprised that my females slowly become gravid again. I don't know, what happened, because I don't use any special food (in fact, currently I feed only with cyclops+beef heart, and my Corydoras don't love it too much, and I add tubifex twice a month). One month ago, I caught all the fish and I found out that one female becomes gravid. I told myself that I shouldn't hurry with another spawning and I let her be. Several days ago I found out that three females are more or less full of eggs. I will wait one more month, and I will add earthworms that now start to be available. Hopefully I will be successful with this fish again.

I don't think that Robineae are just the most abundant Corydoras species. Their imports are quite rare - at least in my country.

[sojapat]

I agree that someone has to try out this way of breeding corydoras,
While there are guys who flip about the use of hormones ,It has brought several species of nearly exinct fishes back from the brink in the Mekong .
Its better to try on a relativley comon fish to gain experience ?
It may be the most viable option with some of the ultra rare fish in the future .
You cannot sit on a species for several years just waiting ,,,they may never spawn and die of old age .... Uh Oh I lost the only ones left because of pride.
There are fishes like synodontis,botia,puntius now being produced like this to take off the pressure from wild collection or just to make them more readily available to the trade.
well thats my thoughts , Might be a bit Dr Frankenstine but think about it

[Jools]

I tend to agree with Neil, especially around the point on taking pressure off wild stocks. I still also think that it is more of an achievement to "crack the recipe" for natural captive spawning for any given species, but in cases of potential extinction (I was very sorry this week to learn of the fate of

Rhizosomichthys totae

for example) it's the nuclear option.

I recently looked at a basic aquaculture manual PDF, and it's not for the feint hearted. However, to do it for profit, where wild stocks or starving humans are not materially effected?

So, it certainly has its place, but I'd suggest, out with of rare conservation projects, it's more in the world of aquaculture.

Jools

[MatsP]

Jools and I had this discussion one day at the CSG conference (or the day before, I believe), and the conclusion was, in order of preference:
1. Captive bred "au naturel".
2. Captive bred "by force".
3. Wild caught.

This applies to commercial breeding on large scale. Individuals breeding fish for hobby, I think should aim for the achievement of doing it naturally.

--
Mats

[Mike_Noren]

From an environmental point of view wild caught is clearly preferrable.

Collection have little effect on wild stock and provide an incentive to protect habitats and stocks, while captive breeding effectively render wild stock worthless.

The one species known to me which is considered threatened by collection for the hobby is Puntius denisonii, and I personally think that's in error; I believe there is not only a confusion regarding which species is under what threat, but that the real threat against also these Puntius species is the same as threatens most wild populations of freshwater fish all over the world: overfishing for food, overutilization of water for irrigation, and habitat destruction due to development, logging, and conversion to farmland.

From an aquarist's viewpoint forced breeding or "natural" breeding is largely irrelevant, although in the long run hormonal breeding will cause the loss of natural behavior.