Breeding Question

[cmstwc]

There are 11 WC C. Sterbai in my 30G breeding tank. Lately, spawning occurs almost on a daily basis. My observation leads me to the following question. One of the female is having a much smaller cluster of eggs (range from 3-7 eggs) every time compares to the other two female (about 26-32 eggs). Does anyone know what is the primary reason causes this difference? Thanks!

[MatsP]

One possibility is that the female with few eggs is getting less food. Another is that she harbours some sort of parasite (almost every wild-caught fish carries some parasite after capture, but good wholesalers get rid of most of them).

But I'm no expert on this, so someone else may have a better idea.

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Mats

[cmstwc]

Thanks for the reply. I am certain that she gets enough food. Should I try to de-parasite them? They are in my tank for 1 year now. I have never done internal parasite treatment before. I am kinda worried right now.

[MatsP]

Generally speaking, treatment for internal parasites is not a bad thing. They are generally harmless unless you are overdosing by factors of 10.

But it's really your choice, it's not my fish, and I wouldn't want to be told something like "Well, I took your advice, and now all my fish are dead" - I don't think that will happen, but it must be your decision what you want to do.

In balance, you have to weigh the factors - the fish is obviously not dieing if it's laying eggs - it's just not as productive as the others. So the question is whether there is something to "fix" - according to the principle of "if it ain't broke, don't fix it"...

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Mats

[cmstwc]

What would you recommend me to use in this case? I have read Waterlife Octozin does a pretty good job on removing internal parasite, but its hard to find in US. Is there an equivalent product that I can find in LFS? Thanks again!

[MatsP]

I would probably use something Flubendazole-based. There is a product in this country called "Kusuri Wormer Plus", which I've found works well. I'm sure someone in the US would be better placed to answer. However, I have heard good things about "Jungle Parasite Clear", which is a cocktail of several parasite medications in one.

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Mats

[apistomaster]

It seems normal to me. Often only some of the available females actually participate in a spawning group during any given spawn so that one should only produce fewer eggs is probably more an indication that she only laid the eggs she had that were ripe during the spawning flurry.

[cmstwc]

Thanks Mats! I will get Jungle a try!

[cmstwc]

It seems normal to me. Often only some of the available females actually participate in a spawning group during any given spawn so that one should only produce fewer eggs is probably more an indication that she only laid the eggs she had that were ripe during the spawning flurry.

Is it still normal if that female keeps laying eggs for 5-6 hours and each time only deposit 3-7 eggs?

[Mod edit: Un-disable BBcode so quote tags work OK --Mats]

[apistomaster]

Yes, because fish are not machines stamped out of molds and are subject to individual differences for very many reasons.
If you were to segregate the fish in question and feed it live black worms for 2 weeks then try to breed it it may lay a 100 eggs.
Or it may be that particular fish just isn't as fecund as average. You need to allow for individual differences and circumstances.
I have had many different outcomes breeding Corydoras sterbai and have raised about 2000 of them over the years. I never have any expectations for any particular specimen. i breed them in groups and as I said earlier, not all females in a spawning group will always even lay any eggs at all.

[Coryologist]

Is it still normal if that female keeps laying eggs for 5-6 hours and each time only deposit 3-7 eggs?

Greetings. Unless you are sitting there without taking your eyes off of the fish for even a single moment, during that 5 to 6 hour period, you have no way to determine how many eggs are being lost to predation. I have watched many spawnings where eggs were eaten as fast as they were laid. I have witnessed a second female shadow the laying female and consume most of the eggs as they were deposited.

I watched a C113 lay eggs today and the female that laid them ate half of them within minutes of laying them, even before I could get them covered up so she could not get at them while they hardened, so I could remove them from the tank.

There are a lot of people who believe that Corys do not eat their eggs. These are generally individuals who do not have the luxury of being able to watch their Corys, uninterrupted, for hours on end, as they spawn.

Additionally, 90% of my spawnings take place while I cranking Z's and I awaken to find eggs in the morning. Who knows how eggs many were lost to predation? I believe that number can range anywhere between 0% and 100%.

Just something to consider. - Frank

P.S. If there is one thing I have learned in spawning Corys, it is that the word "normal," rarely applies.

[cmstwc]

Yes, because fish are not machines stamped out of molds and are subject to individual differences for very many reasons.
If you were to segregate the fish in question and feed it live black worms for 2 weeks then try to breed it it may lay a 100 eggs.
Or it may be that particular fish just isn't as fecund as average. You need to allow for individual differences and circumstances.
I have had many different outcomes breeding Corydoras sterbai and have raised about 2000 of them over the years. I never have any expectations for any particular specimen. i breed them in groups and as I said earlier, not all females in a spawning group will always even lay any eggs at all.

Thanks Larry! I think that is kinda explained my curiosity. I have read quite a bit cory breeding articles online & in magazine, but no one has ever addressed this issue. (at least not that I can remember) I was just very curious to see if anyone on this forum has experienced this and know what is the real reason causing this difference if there is one besides than individuality.

[apistomaster]

There are so many reasons, predation by the breeders, as Frank explained, and so many others that it seems it is over analysis to come up with more reasons why a fish behaves a certain way. Think less about that fish and become more experienced with the species until you accept the variations from what you come to accept as typical. In short, chalk it up to experience.

[cmstwc]

Is it still normal if that female keeps laying eggs for 5-6 hours and each time only deposit 3-7 eggs?

Greetings. Unless you are sitting there without taking your eyes off of the fish for even a single moment, during that 5 to 6 hour period, you have no way to determine how many eggs are being lost to predation. I have watched many spawnings where eggs were eaten as fast as they were laid. I have witnessed a second female shadow the laying female and consume most of the eggs as they were deposited.

I watched a C113 lay eggs today and the female that laid them ate half of them within minutes of laying them, even before I could get them covered up so she could not get at them while they hardened, so I could remove them from the tank.

There are a lot of people who believe that Corys do not eat their eggs. These are generally individuals who do not have the luxury of being able to watch their Corys, uninterrupted, for hours on end, as they spawn.

Additionally, 90% of my spawnings take place while I cranking Z's and I awaken to find eggs in the morning. Who knows how eggs many were lost to predation? I believe that number can range anywhere between 0% and 100%.

Just something to consider. - Frank

P.S. If there is one thing I have learned in spawning Corys, it is that the word "normal," rarely applies.

Thanks Frank! Congrats on the spawn!

In fact, this tank is right next to my desk. I spend most of my day time at my desk. So this tank is really 1 foot away from me. I did notice that other non-breeding participators would steal the eggs after the female place it. However, I did catch almost every single moment when they spawn. Literately from the beginning T-position, to eggs falling out, to eggs placed onto somewhere. And I watched them repeatedly doing it. There really isn't a big difference regarding the average time that the two females spend on T-position. (And I counted it when eggs fall out from her.) Another interesting observation is that the female lay fewer eggs each time tends to be very cautious of where to place her eggs. She would swimming around for minutes before she satisfy with the location, and she would almost never place it anywhere that is easily to reach (for other fish). Compare to her, the average laying 30 eggs female would place her eggs about 1-2 minutes after T-position, and she pays much less care on the location. My thoughts was that smaller cluster of eggs (but much longer spawning time) + "better" locations imply experienced (?) breeder, and the other one is less experienced (?) This is really my hypothesis. I hope someone can help me justify my assumption.