PROBLEMS WITH DYING FRY

[Jackster]

Well honestly one of my tanks was a total loss. I tried the chemical that was
recommended (machalite green) and I believe that it actually killed the fish
faster due to the already advanced state of the parasitic infestation in combination
with the toxic nature of the treatment (just my opinion). As a last chance effort short
of bleaching everthing, I used a one time treatment of potassium permanganate
in another tank at an extremely low dosage (2mg/liter) in combination with the .1-.2%
salt concentration for 14 days and it worked. The remainder of tanks infected
contained a wide variety of species including Black Ghost Knife and African catfish
so I was fearful to use PP and just used salt and again it worked. I also recently
discussed my experience with a fellow fishkeeper and he shared a fact with me
that I was not aware of. His opinion (or theory) about chilodonella is that it
actually thrives in very clean water which may be the case in bare bottom or fry
tanks when doing very frequent water changes and the fact of these type of tanks
also somewhat lacking in heavy bacterial activity. The cure he suggested was to
actually dirty up your tank with more beneficial bacterial to help control the parasite.
After considering what he had said, I was like WOW at the time of my outbreak
I was doing extremely frequent water changes at about 40% every 2-3 days and
I realized what he explained was making perfect sense. Although I believe the actual
contamination came in with some "dirty" fish my particular tank maintenance
shcedule may have also been a contributing factor to the parasites dramatically
increasing in numbers to the extent of a major problem.

[apistomaster]

With all due respect, I have to say that the conclusion that Chilodonella thrives in clean water but not in dirty water is nonsense.

Not only that, but what can be shown to be true is that medications are rendered less to not effective in aquariums containing an excess of organic waste.

No one can be treating fish correctly without a thorough examination and identification under a microscope of the causative organism(s). No professional fish pathologist in the world would disagree with this assertion.

Everything else is guessing. Maybe experienced guessing but a guess none-the-less.

There is so much that aquarists do or believe that has no basis in fact. That is why they are called hobbyists instead of professional aquaculture specialists.

[cartouche]

I think I start to understand, what happens with the fry. I just had my first big bunch of Sterbai fry (65 pieces out of 151 eggs), which was a big relief after so many failures. (I can't place more than 15 eggs+1 drop of methylene blue in a container, irrespectively of its size - I don't know why, but the most important thing is that I have some fry eventually.). The fry were 3 days old yesterday, and I observed that some of them behave strangely. Today, 10 were dead and some of the remaining ones behave exactly like the fry of duplicareus and trilineatus - they haven't consumed their yolk sac yet, shake, move lethargicly and some desperately try to breathe at the surface, although there is certainly enough oxygen in the tank. At the same time, I have (or already had) several other small bunches of Sterbai fry (ca. 10 pieces each) and they develop(ed) normally. So it is clear that the problem isn't in the water.

I think that there are some infusoria multiplying from the dirt in the tank (e.g. egg remains etc.) and they are attacking the fry's gills. When the fry "shake", they actually try to breathe more quickly.
I already moved the remaining sterbai fry into a new container with one drop of ESHA 2000.

As for my last bunch of duplicareus (20 pieces), they are 3 days old now and they are still alive. But that's not a sign that everything will be O.K., because the problems usually start on the 4th day. In any case, I added a drop of ESHA 2000 into the container with duplicareus shortly after I moved them there after hatching. I am curious, if there are some changes in the fry's behaviour.

[apistomaster]

I have considered something simlar in that what is happening mayy be a bateria not necessarily a specific fish disease organism that when present may be affecting the neonatal Corys resulting in death.

Perhaps analogous to E.coli in humans. Normally present and harmless but under certain circumstance an/or certain strains may cause disease.

To get anywhere with this hypothesis would be a considerable undertaking. A lot of controlled experiments and perhaps culturing suspect bacteria.
Basically beyond the scope we hobbyist can take on.
Hopefully something concrete will emerge that we can act on as practical fish breeders that will reduce these early losses of fry.

[Coryman]

Cartouche

Do you only use BBS as the first food? I have found this not suitable for all species. Do you not use micro worm.

Also what triggering method do you use to induce spawnings.

Ian

I have no experience with microworms. I would rather prefer Paramecium, but I can't get to any clean culture. But as I said, it has hardly anything to do with feeding. By the way, most of the trilineatus that I spoke about above were dead before 3rd day. But during the last days I observed something: My little sterbai (luckily hatched from chronically fungusing eggs) behaved the same way, i.e. didn't eat, didn't consume their yolk sac and eventually died, if I started to feed them one day earlier than usually. Perhaps the water really contains some bacteria or infusoria that prevent the fry from normal development.

I just have new eggs from duplicareus and if they hatch, I will try to make some videos or photos, how the fry develop.

I did ask another question "What triggering method do you use to induce spawnings" If I remember right you favour the use of hormones, is this how you trigger these so called problem species?

Ian

I did ask you a question, two actually, which so far you choose to ignore.

The main one being your method of triggering or inducing a spawning and if you are using hormone treatment to do this. If this is the case have you thought about the possible damage to any offspring through this treatment.

Ian

[cartouche]

Cartouche

I have no experience with microworms. I would rather prefer Paramecium, but I can't get to any clean culture. But as I said, it has hardly anything to do with feeding. By the way, most of the trilineatus that I spoke about above were dead before 3rd day. But during the last days I observed something: My little sterbai (luckily hatched from chronically fungusing eggs) behaved the same way, i.e. didn't eat, didn't consume their yolk sac and eventually died, if I started to feed them one day earlier than usually. Perhaps the water really contains some bacteria or infusoria that prevent the fry from normal development.

I just have new eggs from duplicareus and if they hatch, I will try to make some videos or photos, how the fry develop.

I did ask another question "What triggering method do you use to induce spawnings" If I remember right you favour the use of hormones, is this how you trigger these so called problem species?

Ian

I did ask you a question, two actually, which so far you choose to ignore.

The main one being your method of triggering or inducing a spawning and if you are using hormone treatment to do this. If this is the case have you thought about the possible damage to any offspring through this treatment.

Ian

Dear Ian,

First, I have never said that I prefer hormones. It is ever the last alternative.
Second, do you think that Duplicareus need to induce spawning?

[Coryman]

cartouche,

I was not trying to draw you into a debate on the use of hormones, you already know my views on that subject.

However in a previous topic you were arguing in favour of hormone induced breeding, so I was only curious as to whether you were using this method to induce spawning with the species you are having the fry problems with.

Most species will need some sort of trigger to start a spawning session, whether it be just a normal water change or a dedicated pattern of events. My questions were aimed at finding out what method you used to trigger these species and to see if there were any clues in these methods as to why the fry were not surviving.

Ian

[cartouche]

cartouche,

I was not trying to draw you into a debate on the use of hormones, you already know my views on that subject.

However in a previous topic you were arguing in favour of hormone induced breeding, so I was only curious as to whether you were using this method to induce spawning with the species you are having the fry problems with.

Most species will need some sort of trigger to start a spawning session, whether it be just a normal water change or a dedicated pattern of events. My questions were aimed at finding out what method you used to trigger these species and to see if there were any clues in these methods as to why the fry were not surviving.

Ian

No, it really has nothing to do with hormonal injections. It is - as one breeder already suggested to me (and I didn't believe him) - some infusoria or bacteria in the water. From the big bunch of sterbai I have lost another 4 pieces since yesterday and some other pieces also don't look well. They are 5 days old already, so all of them should already have their yolk sac consumed, but they behave like the dying duplicareus and trilineatus. But hopefully the majority of them will be O.K. The duplicareus fry are 4 days old now and they are still O.K. However, they still have very big yolk sacs and I don't know, if I should start to feed them or not. Normally, before the problems started one year ago, I would start to feed them on the 4th day; but recently I observe that if some of the fry survive, they consume their yolk sac and start to eat as late as on the 5th day.

[Coryman]

cartouche,

I was not trying to draw you into a debate on the use of hormones, you already know my views on that subject.

However in a previous topic you were arguing in favour of hormone induced breeding, so I was only curious as to whether you were using this method to induce spawning with the species you are having the fry problems with.

Most species will need some sort of trigger to start a spawning session, whether it be just a normal water change or a dedicated pattern of events. My questions were aimed at finding out what method you used to trigger these species and to see if there were any clues in these methods as to why the fry were not surviving.

Ian

No, it really has nothing to do with hormonal injections. It is - as one breeder already suggested to me (and I didn't believe him) - some infusoria or bacteria in the water. From the big bunch of sterbai I have lost another 4 pieces since yesterday and some other pieces also don't look well. They are 5 days old already, so all of them should already have their yolk sac consumed, but they behave like the dying duplicareus and trilineatus. But hopefully the majority of them will be O.K. The duplicareus fry are 4 days old now and they are still O.K. However, they still have very big yolk sacs and I don't know, if I should start to feed them or not. Normally, before the problems started one year ago, I would start to feed them on the 4th day; but recently I observe that if some of the fry survive, they consume their yolk sac and start to eat as late as on the 5th day.

cartouche,
You still have not answered the questions. Stop acting like a politician and give some straight answers to the questions instead of side-stepping them.
Another one, have you tried R/O water with just the necessary additives to create the required hardness.

Ian

[cartouche]

I tried various mixtures, but with zero result. My duplicareus hatch at 7 dGH, pH 6,5-7. Or at 4 dGH, pH 7,5.

I usually use the former, because it is easier to mix. I have several sources of water from which I can get this chemistry.
The best results were in 75%Rain water+25%Well Water. Sometimes 50% fry survived.
In 75%Destilled Water+25%Well Water there was almost always 100% mortality. Results in 30%Rain Water/Destilled Water+70%Tap Water, or 5 parts Bought (packaged) water from the shop+1 part of Well Water, were not much better. Nothing worked like before.

Hmmm, in the evening I observed that 2 out of those 20 duplicareus are already dead.
It usually starts this way on the 4th day. Tomorrow there will be probably a massacre already. None of them have completely consumed their yolk sac. In fact, it has virtually the same volume like after hatching. Hopefully tomorrow I will add some photos.

[Coryman]

cartouche,

OK Now I know what water you are using. The next questions:
What method of trigger do you use? 1) None at all. 2) Cold water change, if so what is the temperature reduction. 3) Artificial, if so what. (If is is hormones then say so, I am not interested in debating ethics I am trying to help find the reason for the deaths). You said this is not the cause of the deaths, but how do you know? have you examined or had a post-mortem done on any of the dead fry to find out. In the light of the number of fry you are loosing i think that would be one of the first things to have done.

Do you always remove the eggs or have you tried removing the adults and hatching the fry in the tank where the eggs were laid. I always find this has better results.

Ian

[hellocatfish]

Have you ever tried taking the well water entirely out of the equation? Friends of ours went to sell their house and to their shock during their home inspection they learned that their well water tested positive for elevated levels of bad bacteria. Not enough evidently to make a healthy or acclimated person sick, but I suppose anyone with a weakened immune system would have had some trouble with it.

[cartouche]

Have you ever tried taking the well water entirely out of the equation? Friends of ours went to sell their house and to their shock during their home inspection they learned that their well water tested positive for elevated levels of bad bacteria. Not enough evidently to make a healthy or acclimated person sick, but I suppose anyone with a weakened immune system would have had some trouble with it.

Well, I must describe it in a more detailed way.

First of all, I don't use any triggering method. I have 31 duplicareus in a 130-liter tank. I feed them with beef heart and plankton (cyclops, daphnia, mayfly larvae), sometimes I add earthworms. They spawn virtually all the year round spontaneously, 1-2 times a week. I suppose that the females interchange in spawning, so sometimes I can get as much as 400 eggs a month, sometimes less than 100. After the spawning I remove the eggs from the tank and give it into a small (1,5 liter) container with appropriate chemistry. The temperature in the tank with adults is ca. 22 C, but I hatch the fry at 26-28 C. I add one drop of methylene blue, because it helps against fungus and bacteria that desintegrate eggs. At this temperature, they hatch after 4 days. I usually let them in the hatching container, which may not be good, because the desintegrating egg remains can influence water cleaness. However, it was not much better even if I removed them into a new water.

As for well water, it wouldn't change anything. As you can see from my description, even combinations without well water didn't work. In fact, the most lethal combinations are well water+destillated water and tap water+rain water. Absolutely different sorts of water. On the contrary, the best water is usually well water+rain water.

As I described above, the fry simply don't consume their yolk sac and die after 4-5 days. I know how the normal development of duplicareus looks like. I have bred them since summer 2003 to December 2005 successfully, they developed normally and started to eat after 4 days. I even placed them into tap water shortly after hatching and it didn't hurt them. Now, since December 2005, they don't develop and die. And if they survive, they eat as late as after 5,5-6 days.

As for the bunch that I just have, another 2 were dead this morning, which means that 16 out of 20 are still alive after 5 days... Which is not bad at all, because usually they are all dead after 5 days. I observed that some are already thinner, but most of them still have very large yolk sacs. I tried to feed them with live artemia yesterday, but they didn't eat yet. So I removed the artemia and I tried it today at noon. But again, I think it's too soon. So this bunch, removed into a new, identical water after hatching and treated with ESHA 2000, doesn't behave differently from other bunches that I had during the last year. They - if they survived - namely started to eat as late as after 5,5-6 days since hatching.

I know that it is hard to give some advice, if you don't see it on your own eyes, but I still hope that someone could have similar experience. Or am I the only in the whole world, who has such problems?

[apistomaster]

It is hard to imagine what could alter the natural rate of larval development you describe. The absorption oof the yolk is genetically programmed. Low temperatures might slow that down but I'm sure that is not a factor in the case of your spawns.

Are there any other fish you raise unrelated to Corydoras that can be used as controls?
Perhaps a species of Tetra, something that hatches fast and takes 5 more days to go free swimming to see if this is a general or specific problem.

What you are experiencing is reminiscent of the old problem discovered in raptors and DDT where the egg shells of these bird was becoming so thin that they were being crushed during normal incubation. Well waters are subject to herbicidal/insecticidal contamination just to cite a possibility. I know that this is not unheard of in the Pacific Northwest.

I am working with the following Corydoras species:
C-121, duplicareous, hastatus, sterbai, panda, habrosus and erhardti.

I live relatively near you and as close as 33 miles away from me there are problems with phosphates and nitrates from extensive agriculture has effected some cities public wells. I also have city water from deep wells but we have no problems with any contaminates. The wells are deep enough that the water is essentially "ancient" water.

[cartouche]

Even the combinations in which I use no well water didn't work. I already stated it above. Perhaps I should try Rain Water+Tap Water once more, with ESHA 2000 and including removal of the fish into a new water after hatching.

I don't breed any other species except Corydoras. But this strange behaviour doesn't occur in C. napoensis, S. barbatus and (with some exceptions) in C. sterbai. As I already stated, it occured in one bunch of Sterbai that I started to feed one day earlier than usually. And it occured in my new big bunch of ca. 60 Sterbai fry (10 out of 60 were dead on 4th day and even after 6 days, the dying continues, with some pieces lying on the bottom, still with visible yolk sacs and not eating.)

In any case, it always occurs in Duplicareus and Trilineatus. I think the case with Sterbai and Trilineatus is just a proof that it has nothing to do with the sort of water that I use, because Sterbai and Trilineatus are hatched in normal tap water.

I just looked at the duplicareus. Another was dead (5th out of 20), but the remaining ones look relatively well. I know from experience that if they survived 5th day, they started to eat and were O.K.
75% survival would be something that I haven't experienced since spring last year.

[apistomaster]

Hi catouche,
Since I have my own frustrating issues with survival of my own Corydoras I did not commit to memory all the details of yours.
What you are experiencing is very dfferent as it seems for some reason the normal deveopment of the fry of SOME of your Corydoras species is difficult to pin down.
My fish absorb their yolks on time but begin to die mysterious deaths until the surviving fish make the tranformation to the basic Corydoras body plan.
I'm sure you will get to the bottom of your difficulties.
Corys are just part of what I raise. I produce discus, Apistogramma, Tetras and other fish. I just don't have all my eggs in one basket. (Pun intended.)

[hellocatfish]

Is barometric pressure a factor at all in the development of fry? We have had very odd weather patterns and sudden temperature flip-flops recently and I noticed that is what seemed to trigger my paleatus acting kind of nutty and seeming to spawn or become aggressive or whatever it was that had them crashing around the tank wrapped around each other...driving everyone to distraction. I also know from reading that barometric pressure changes are spawning triggers in their native habitat, as well as the temperature drops from the rains that follow. I just wonder if that is all of the role that barometric pressure plays in their life cycle. Maybe with some of the cories it does not matter at all, and maybe with some it does affect the fry.

Maybe there's something about your northwestern environment that is at odds with deeply programmed attunement to their native southern environment.

Another possibility that comes to mind is the absence or deficiency of some kind of enzyme or protein catalyst that could help them digest their yolk on time. Or a delay in the production of it. That's the mom side of me talking--I remember freaking out when I found out I was several weeks pregnant, because I had not been taking any folic acid supplements and I was worried if that would affect my baby's spinal cord development. I wonder how long people floundered about trying to find out what caused spina bifida before it was discovered one nutrient in insufficient quantities coupled with a genetic component could cause such a devastating developmental catastrophe.

[cartouche]

Thank you for your suggestions. But anyway, it's a mystery. But the idea with the lacking enzymes/vitamines is not bad. Perhaps I should try to do something with the diet that I give to my fish. I already tried to change it, but perhaps they still don't get some important substance. Before the problems started I fed them with granules and bloodworms. Now I feed them with beef heart and frozen plankton that mostly consists of mayfly larvae and a bit of daphnia.

Fortunately, the last bunch of duplicareus is still alive after 6 days (15 out of 20 pieces). I wouldn't bet that they all will survive the next days, but if they are alive after 6 days, I shouldn't experience any serious loses. I observed that my Duplicareus again spawn today, so I will try to make two groups - one without desinfection (ESHA 2000) and one with it - if there is any difference.

[apistomaster]

Hi cartouche,

I will expose my ignorance here but what the heck, what is the disinfectant, ESHA 2000? I'm not familiar with it. I only have experience with methylene and acriflavine as an egg antifungual agent.
As it understand it they are not the same thing as an egg disinfectant as products are used in commercial aquaculture for that purpose. I have considered trying an egg disinfectant in lieu of anti-fungals.

[corydoras]

Hi Cartouche

How long have your breeding group of duplicareus been in the 130L tank? I presume that they are the one fish in there? The reason I ask is that I have noticed in my own fish house that long term corydoras breeding set ups develop a thin film or slime on all glass surfaces inside the tank. I can't see the film from the outside of the tank, but I can feel it if I lightly pass my finger over the inside of the glass.

I have never tested what it is but a assume that it's a bacteria film. One thing I have discovered is that it affects spawning corys as they don't seem to like laying eggs on it. I have always been suspicious of it affecting eggs. It is probably made of of good nitrifying bacteria but you cannot be sure. If it is on the glass, it will also be on the eggs and transferred to the hatching container when moving the eggs. It could be then proliferating in the hatching container.

There are two solutions, one drastic and very convenient. The drastic measure is a total strip down and cleaning, the convenient is putting a couple of young bristlenose cats (ancisturs sp.) in for a week or so. They clear it all away.

If your tank has been permanently set up since 2003 with little change, then, maybe, possibly, your tank set up is now a little weary and needs a major overhaul. A fresh set up may make a difference. I personally don't let long term breeding set ups go much more than a year, if that.

Cheers

Matt

[corydoras]

Hi Larry

Esha 2000 is a broad spectrum bactericide which is available over the counter in many LFS's in europe. It's marketed by Esha labs.

I also claims to eradicate fungus and parasites as well, so it is a real 'catch all' treatment. I've never personally used it, but I think it's based on the traditional ingredients that you are experienced with. It has a good reputation, so I've heard, but as I already have my favourite brands that I know work, I have never had the urge to give it a try.

Cheers

Matt

[apistomaster]

Hi Matt,
Thank you for that information.I first heard of in in this thread.

Bet you get some flack about the possibility that there may be a bacterial slime inside the tanks if they have been in use for awhile. I at least wipe to surfaces clean prior to a large water change because Corydoras do seem to prefer a clean surface to attach their eggs to.

I also start from scratch and retain some of the old water to mix with new.

[cartouche]

ESHA 2000 was recommended to me by one breeder. He has big success with it. He even says that if you add it into a tank with eggs, the healthy eggs don't catch fungus from fungusing eggs.

As for the tank, it has been running since 2004, I think. I don't know, if I can transmit some bacteria on eggs, but I am virtually sure that they can get into water through air stones from the air in the fishhouse. One year ago I had chronical problems with fungusing eggs of duplicareus. One breeder suggested that it may be due to heavy concentration of anaerobic bacteria in the air of the unaired house (it was in winter). They invade egg covers and the eggs subsequently catch fungus. At first it seemed improbable to me, but after I started to air my fishhouse, the eggs of duplicareus ceased to fungus. Curiously, it was also the time, when the problems with the dying fry started. I bought new stands and tanks then and, naturally, with the increasing humidity in the fishhouse, I started to encounter problems that I have never had before.

I also tried acriflavine against it, but it helped only weakly. Methylene blue was much better. In any case, if the eggs now successfully hatch (I collected ca. 30 altogether today), I will see if the fry survival has anything to do with ESHA or if it is only a coincidence. It is really interesting, because my last bunches perished completely. The last one has 75% survival rate so far, which is very encouraging. I observed that the fish have orange spots in their bellies, which means that they already started to eat artemia. However, most of them still have very big bellies (yolk sacs) that you really wouldn't expect in such old fry. Unfortunately, my camera is currently unserviceable.

I also have a bunch of freshly hatching Corydoras trilineatus. I will also give them in a water containing ESHA. If they survive, then the connection will be practically clear, because all my previous bunches had miserable survival rate.

[cartouche]

I continued with my attempts with ESHA 2000 and guess what happened: The fry that are placed in a tank with a drop of ESHA survive...! On the other hand, if I use methylene blue - or if I use nothing -, they die after 3-4 days like before...

It seems that ESHA is not especially effective against my problems with fungusing eggs (here using methylene blue is comparably efficient), but it is obviously highly effective against the problems with fry. So there may really be some micro-beasts present in the water that kill the fry. What a relief for me! I already intended to sell all my breeding group of C. duplicareus, because I haven't raised a single piece of fry since December!

[Coryologist]

Greetings, I have been following this thread with great interest, as I, too, have problems with C. duplicareus fry. I promised myself I would keep my nose out of it as I can see that this can be a testy subject, but I have to stick my 2¢ in at this point.

I tried a little experiment of my own. I took half the eggs from a single spawn and placed them in their own tank, which is untreated. I took the other half (16 eggs) and placed them with eggs from C. weitzmani, C, simulatus, C. nattereri and S. prionotus and placed them in an untreated tank. All the eggs hatched in the normal 3 to 5 day time frame. All the wigglers were quite active and no physical deformities of any kind were observed.

Within 5 days of hatching, it was easy to see that the C. duplicareus were lagging behind in growth and mobility. Every other fry in the tank was doing fine. By this time I was able to look at an individual specimen and declare that it would be dead by morning. I was always right. They just looked weak. Once they start to shimmy in place, they are dead meat!

When you have 4 of 5 species thriving, I would not choose a "bug" as my first guess for what is causing the problem. Are the other species immune to the "bug?" I would guess not. My C. duplicareus have been spawning regularly for well over a year. I lose a majority of the fry within 14 days. Personally, I think this is a result of poor genetic vigor in the specie. I have no way to prove this of course, but when 1 out of 5 species falters, it is the most logical, though hardest to prove hypothesis.

The ESHA test, having only been tried once, reveals nothing that can be concluded as fact. It could be nothing more than coincidence. I would like to see this repeated a few more times, before I would give it any creedence, whatsoever. Additionally, I would only consider it a fact when I can personally duplicate the results in my own fish room.

Please accept my missive in the spirit with which it is proffered. I am not trying to be confrontational, nor, argumentative. Just trying to find a valid solution to a problem that I believe will take much more research, by different individuals to see if the results can be duplicated. Until then, the results have no scientific validity and can only be classified as anecdotal.

A single drop of anything, being a magic cure, to my way of thinking, just doesn't hold water (no pun intended). Would be vey interested in seeing who is able to duplicate the results that cartouche has achieved on a regular basis.

I for one would be interested in participating in such a group experiment. Any other volunteers???

Regards,

Frank

[apistomaster]

Hi Frank,
I commend you on the beginning experimental work you did but you came to the wrong conclusion, imo. I mean this with a respect. I think the results of your work and our collective experience points to is that Corydoras duplicareous is a demanding species. I mean this in the sense that we probably need to come closer to providing their eggs/fry with more specific conditions.
I say this because I believe we are all breeding wild fish which are genetically perfect for their native environments but we are not meeting their needs adequately in aquarium captive breeding setups.

They are obviously a successful species or we would not have them, they would have gone extinct long ago.

The challenge is to better duplicate their natural environment and in the meanwhile realize we are working with a Corydoras species that is more exacting than most from a fish breeders viewpoint.

There are many examples of challenging fish to breed in captivity. Cardinal Tetras, Dicrossus filamentosus, and Heckel Discus to cite some examples.
They are all successful in their native haunts but very difficult to raise in captivity.

I am in this with everyone else and I'm sure we will get to the bottom of our problems by doing more experimental work as you did.

[Coryologist]

Hi Frank,
I commend you on the beginning experimental work you did but you came to the wrong conclusion, imo. I mean this with a respect.

Hi Larry. Well, first-off, I have not reached any conclusions, at this juncture. Just a simple observation.

I think the results of your work and our collective experience points to is that Corydoras duplicareous is a demanding species. I mean this in the sense that we probably need to come closer to providing their eggs/fry with more specific conditions.
I say this because I believe we are all breeding wild fish which are genetically perfect for their native environments but we are not meeting their needs adequately in aquarium captive breeding setups.

This is strictly an assumption that cannot be supported by any evidence. You have a 50% chance of being correct and an equal chance of being wrong, obviously. I don't think we're ready to do spectrum analysis of our tank water looking for minute traces of a single chemical or nutrient that affects the viability of fry from any specie. Nor do I believe that there is a microsopic food source that we are missing, which is required to get the fry off on the right foot. Why just this specie?

They are obviously a successful species or we would not have them, they would have gone extinct long ago.

"Successful" is an extremely relative term that cannot be quantified. Most scientist/ichthyologist/marine biologist feel that in nature, most specie of fish, mollusk, crustacean and the like, survive at a 1% rate to reach adulthood. Forgot those dang sea turtles, too. That's 1%. For all we know there is a genetic defect. Possibly, a few thousand years ago they were found in far greater numbers than today, when they were more genetically strong. Lets take loss of habitat and toxins out of the equation. I am not proposing that this is the case. Simply illuminating the myriad possibilities that can have an effect on any specie. We don't know and I'm willing to wager, that we never will.

The challenge is to better duplicate their natural environment and in the meanwhile realize we are working with a Corydoras species that is more exacting than most from a fish breeders viewpoint.

This is not an attainable goal. Replicate which natural environment? The dry season? The rainy season? The variations in temperature, pH and other water parameters, as well as potential food sources, or lack thereof, rendrs this type of "biotype replication" an exercise in futility.

There are many examples of challenging fish to breed in captivity. Cardinal Tetras, Dicrossus filamentosus, and Heckel Discus to cite some examples.

How do we know if they are any more or less difficult to complete successful spawning in nature. Simple answer: we don't. For all we know it make take 100 breeding attempts in nature for a successful spawning to occur.

They are all successful in their native haunts but very difficult to raise in captivity.

Again. How successful? 1 in 2? 1 in 10? 1 in 100? We do not and will not ever know the answer to that question. They may be just as difficult for them to survive in the wild, as in our tanks. These are unanswerable questions.

I am in this with everyone else and I'm sure we will get to the bottom of our problems by doing more experimental work as you did.

Well, I honestly feel that most hobbyist do not have the capability to ascertain the validity of any hypothesis we may offer up.

I try to never "beat a dead horse, and I'm afraid that's what we are doing here. It may be fun to talk about, but in the end we don't know jack-squat about how these fish truly reproduce in nature, especially as it relates to successful spawning attempts and the number and viabilty of fry.

So, in closing, I shall stop beating the dead horse, but I hope I have shed some light on the lack of true scientific research and experimentation that we are capable of.

I once bemoaned to a preeminent Cory expert my thoughts about this subject. His advice? "Be happy for the fry you get, enjoy them as much as possible and forget trying to decipher nature's way of doing things". You know what? That was great advice. Because of the degree of difficulty I encounter, I take great pride in the C. duplicareus I am able to raise successfully and regard the dead fry simply as food for the living. Isn't that "nature's way?"

Regards. - Frank

[apistomaster]

Hi Frank,
That was as very entertaining exercise in logical sarcasm as it was pointless.

What does it all mean?

Don't mean ****, kid.

Have a nice day.
And I do happen to respect you and your experience.
It doesn't have to be mutual to be valid.

[Coryologist]

Hi Frank,
That was as very entertaining exercise in logical sarcasm as it was pointless.

I'm sorry that's how you took it. That was not my intent. I never come looking to stir-up trouble and I was right. I knew better than to stick my nose in, ''cause there is always someone looking to bite it off."

What does it all mean?

It doesn't "mean" anything. Just some thoughts that I'm sorry you found so personally objectionable. I still consider them valid points of discussion. Sorry you don't share that view.

Don't mean ****, kid.

To each his own. That's what makes the world go 'round!

Have a nice day.

And you.

And I do happen to respect you and your experience.

Something I neither seek or desire. I stopped caring long ago about how other's "feel" about me. I'm nothing more than excited phosphurs on a monitor. Why make it personal? You know nothing about me.

It doesn't have to be mutual to be valid.

I have NO idea what THAT means. lol.

I'll bow out, now and leave it to those that can interject non-sarcastic points of discussion.

My bad! - Frank

[apistomaster]

Hello Frank,
I only know you from what I have read in your posts and I can tell when someone is a an accomplished aquarist and that I can learn from the experiences they choose to share.

I have found what you have shared to be very useful and on target. Therefore I have appreciated what I gained from what you have shared.

I am also an accomplished aquarist but I do not have the same depth of experience in the art of raising wild Corydoras as you. My expertise is deeper in other areas.

I quite understand your position on whether one is respected or not is of no consequence. Some people do care and are even pleased to learn they have helped others.

I agree that an aquarium is never an accurate simulation of a fish's biotope. We do what we can and if it is near enough sometimes our fish reproduce.
That is the reward to a breeder of challenging fish.