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FAQs on Callichthyid Catfish (Corydoras, Diadema...) Reproduction

Related Articles: Summer loving: cats in the garden, kittens in the kitchen by Neale Monks, Callichthyid Catfishes

Related Catfish FAQs:  Callichthyids 1, Callichthyids 2, Callichthyid Identification, Callichthyid Behavior, Callichthyid Compatibility, Callichthyid Selection, Callichthyid Systems, Callichthyid Feeding, Callichthyid Disease, Catfish: Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction

Outdoor Corydoras paleatus... Pic by Neale Monks

Re: Salt and heat treatment of Ich... Water chem./FW DH, chatting re Corydoras repro.   7/14/10
Hi Neale,
<Hello Lu,>
Oh great, my other half mentioned adding a few small pieces of ice in the back overflow part of tank, carefully watching the temp.
<It's fine to do this, and you don't need to be paranoid about water temperature. Provided the block of ice is some small fraction of the volume of the tank, less than, say, one-twentieth, the overall water temperature change will be small. The fish will usually dart in and out of the cold, sinking water under the block of ice, and in many cases seem to very much enjoy the sensation. Danios and Corydoras are two fish types that enjoy this sort of thing.>
Too funny. Yes, on the current and species issue. Cool, so glad about the hardness recipe, can't wait to play the weird scientist and mess with this in a five gallon bucket. I promise, I sure won't add to tank directly.
<Excellent. It is fun, and once you've made a recipe that works, you're set for life.>
I don't know if you have ever experienced this, but I thought it was so neat. My Cory cats are mating, and the females clean the glass, carry the eggs between their bottom fins, and place the eggs on the walls of tank, and the plants. I was blown away, so darn cute.
<It is very cute, and yes, I have bred Corydoras. Some notes and photos here:
One of the great mysteries is how the sperm and eggs get together. Males shed their sperm in front of the female, but how she gets the sperm to the eggs is unknown, though one theory is she swallows the sperm, passes it quickly along her gut, and then sheds the sperm onto the clutch of eggs in her pelvic fins a few at a time. Pretty weird, I think you'll agree.
Corydoras catfish are among the most interesting fish hobbyists can keep, and yet so undemanding.>
Of course, after all that hard work, they eat them later, what a hoot.
<Do try rolling the eggs off the glass into a breeding trap. The fry are very easy to rear, by the standards of egg-laying fish at least. I have three generations of them living in one of my community tanks by doing precisely this. Sure, I only rear a few "kittens" successfully, but that's enough if you're just doing it for fun.>
I don't mind, as this keeps fish population down. I feel bad for two of the Cory cats because even though I have provided them with fine sand, two of them have lost their whiskers, it is as though they have no lips at all, poor babies. They seem ok and still eat, they just look pathetic.
<Will soon grow back given good conditions. Technically, it's bacterial decay rather than the gravel that causes erosion of the whiskers. It's just that gravel tends to be dirtier than sand -- contrary to what you'd expect -- and the decaying organic matter on gravel coupled with physical damage to the whiskers means the whiskers erode rather than heal normally.>
Indeed, you are so correct about the butterflies. Again, Neale, it is such a pleasure to email with you, thanks so much and as always happy fish keeping. Be well. Lu
<Good to talk. Have fun! Neale.>

Corydoras Eggs 1/11/10
Dear Neale,
Thank you for answering my questions several weeks ago about the fry.
<Glad to help.>
I have three fry left of the original 120 eggs and the largest is about 1.5 cm. They are about 15 weeks old.
<Doing a good job! When breeding fish, there's so much to learn and get right, that even rearing a very few of them successfully is a small triumph. Since fish will lay eggs every few weeks given the chance (and the right spawning triggers) you'll have many opportunities to try out new things in the future.>
They were in a breeding net in a twenty gallon long tank. The net did not allow much air flow and trapped debris on it that could not be cleaned off within the tank and made the tank get a bad odor.
<One approach is to have two traps. Change them over each week, and clean the one not being used with warm water and a scrubbing brush of some type (a toothbrush is ideal).>
I did do water changes of sorts in the net to try to counter these problems, but the pollution was still bad enough that I thought it was very bad for the fry. We had discussed letting the fry out of their tiny world before, and I did let the seven of them out when I tried to clean the net with a hose, brush, etc., but I believe nothing short of bleach would work.
<Be super careful with bleach. Would recommend instead things that break down easily and harmlessly: hydrogen peroxide, lemon juice, vinegar.>
Within hours the fry began to go missing and during that time I purchased a plastic breeding trap for livebearers. The stores in this area had only ones sized small, which is considerably smaller that the original net. It is about 5cm by 13cm and 6cm to water level. Since I could only find three fry left I gathered them up into the breeding trap (I did not use the lid or the piece that can be put in to separate the adult from the young).
They have been doing well in there for quite a while now and the vents in the trap provide good water flow and it looks so much cleaner than the net did.
The plastic traps float, so they are much more convenient during water changes too. The net did not float and attached to the top of the tank with metal tabs that would often fall off and into the tank.
<Yes, have noticed this.>
My experience was that the plastic one is far superior to the net one, but a larger size would be very helpful.
<Agree. I use a net with suckers rather than metal clips, and find it useful.>
I have a second breeding box that has three fry from another later batch and I was pleasantly surprised that even when they were freshly hatched they did not escape through the vent.
<That's the idea!>
Last night one of the original fry must have jumped out of the trap as he is swimming with the adult Corydoras and Blackskirts today.
<Swimming with the big boys, eh?>
Is it possible that the three fry could have their growth stunted/lives shortened by the confines of the breeding trap?
<Not really, no. Since water mixes inside and outside the trap, there's no dangerous build up of metabolites inside the trap that might stunt growth.>
I am trying to decide if I should put the escaped fry back in the trap, or let the other two out also, or leave him in there for awhile and if he survives X amount of days then let the other two out.
<Assuming he doesn't get eaten by the other Corydoras, the main problem is starvation, with small fry needing finer food than the adults. But given sufficient food, Corydoras fry somewhat over 6 weeks of age compete reasonably well with adult fish that aren't going to eat them.>
I would also like to know if it is advisable to keep different generations of fry together in a breeding box, or even add eggs in with fry.
<Again, there's no direct threat, but smaller fish can lose out at dinner time, so you'll want to watch everyone eats normally.>
I'm attached to these cute fish!
<As you should be!>
Thank you, Rose
<Cheers, Neale.>
re: Corydoras Eggs

Dear Neale,
Thank you. The runaway fry still seems to be doing fine and since he is somewhat transparent (albino) I can see that his stomach seems to be full.
I guess I'll leave him in there and see what happens.
About the breeding trap vents and newly hatched fry, I meant that I thought it was designed for baby livebearers which I thought might be much larger on day one (I haven't kept livebearers yet) and so the new Cory fry could
possibly get out or even get stuck.
<Ah, yes, certainly a worry. But I've never found this to be a problem. Fry jumping out of traps and nets is usually more of a thing.>
Luckily, none of them did. The problem with the Blackskirt that was getting picked on several weeks ago was also resolved (for now) when I moved things around in the tank. Just as you said there are new batches of Cory eggs over and over since they got started, every two to five weeks or so.
<Yes, sounds about right.>
If I ever find them in stock locally I plan to get some low light floating plants I have a list of or moss ball or something to put in the tank (after quarantine and maybe a de-snailing treatment).
<Indian Fern is a good choice, and favoured by fish breeders the world over. Snails are actually quite useful in breeding tanks, provided you don't get carnivorous species that would eat the eggs. Among other things they stir up the substrate, consume organic matter, and even promote the growth of infusoria upon which baby fish can feed (Apple snails were very widely kept for this in the past, before powdered fish foods for fish fry were available). So while removing snails might be sensible, don't be too paranoid.>
Thank you, Rose
<Always a pleasure. Cheers, Neale.>
Corydoras eggs 10/22/09

Dear Neale,
Almost four weeks ago I had a question about Albino Corydoras eggs and you gave me great advice about hatching them in a breeding net there in the main tank. I have been having a wonderful time with them. There were 120 eggs and there are now at least 70 fry visible at any time (don't know how many are hidden under the frame and the seams).
<Fantastic! That's a very good ratio of eggs to fry.>
The fry are now three weeks old. I have the big API water test kit so I am prepared to monitor the water throughout the next phases to detect problems, but perhaps your experience can help me better avoid problems to begin with. Initially I had planned to keep all the new Corys for myself, but there are many more than I expected since most of my Googling found about one-third hatching rates for beginners.
<Indeed. As I say, you've done really well.>
I have already been wondering what to do if I find more eggs, leave them to chance or destroy them!
<If you leave them to chance, they'll be eaten by the next day. But since Corydoras will spawn every few weeks, rearing a batch or two per year is, I find, more than good enough.>
Given the gregarious and bottom-feeding nature of Corys, how many adult Corys can live in a 20 gallon long tank (I have one vacant)?
<Oh, probably ten or fifteen adults around the 5 cm/2 inch mark. Rather more juveniles.>
In an identical tank with seven Blackskirts, how many adult Corys can live in it?
<Maybe ten adults.>
I do weekly water changes of maybe 20% on all my tanks. Since there are so many (some at 1 1/2 cm, some much smaller), I was wondering if it is about time to graduate the fry out of the breeding net.
<Sure. The fry can be mixed with adults once they get more than 2.5 cm/1 inch long.>
I have considered that they should probably have shallow water to surface easily, but am concerned about them having a world so big that it is a challenge for them to find food.
<To a degree, this is a fair concern. But the flip side is if you keep too many growing juveniles in a small (say, 10 gallon or less) tank then water quality becomes an issue, and you'll find fish dying. Since you gave 70 (!!!) to play with, why not experiment with half a dozen in the big tank, and see what happens?>
They were initially fed Hikari First Bites and also brine shrimp, but they have also been introduced to Hikari bottom feeder food and tropical flake.
<A good mix. I've found Hikari foods work well with Corydoras.>
If a 20 gallon will be too large right now, I also have a ten gallon that could be a nursery tank for awhile. Since I have other aquariums going as well, it is a bit more difficult to convince the Mr. that buying more aquariums so I can keep them all is the way to go (yes gentlemen, it does work the other way around sometimes!). Thank you, Rose
<Hope this helps. Nice to hear of your success, and good luck! Neale.>
Corydoras eggs 9/29/2009

Good early morning or late night, I have just found what must be Albino Corydoras eggs in my Cory and Blackskirt Tetra tank. This was unplanned (by me, anyway).
<Nice surprise though!>
I do have extra seeded filters in the tank so it is easy for me to take some of the water and start another tank, and I have brine shrimp to hatch and also Hikari First Bites (I don't know if that works for Corys).
<Does, have used it.>
I read your site (way too much) and I read
but found that this one:
http://www.wetwebmedia.com/FWSubWebIndex/coryreproart.htm was a bad link
<Seems to be working fine now. Try pasting the link straight into your browser and see if that helps.>
Since I discovered these eggs late at night I assume that they would have had time to be fertilized since I read that they usually spawn in the morning.
I don't trust the Blackskirt Tetras with anything that they can fit in their mouths so I was able to take a fish net and bend the handle so I could cover the eggs with net and pin the handle under the hood to hold it
there overnight.
<A floating breeding trap works fine for Corydoras eggs.>
I think it is interesting that they placed these eggs in an area that the Blackskirts never go to, near the surface, far from the plants, in the corner that gets the most light.
<Whether the Corydoras specifically put their eggs there, or simply the Blackskirt Tetras ate all the eggs everywhere else is difficult to say...>
I don't know what poses the greatest risk, moving the eggs off of the glass or leaving them in there where they can't be treated with something like Methylene blue for fungus.
<Removing the eggs isn't as difficult as you think. Use a finger to gently roll each egg, and the egg will fall down into a net or plastic cap you've placed underneath. While you might lose a few this way for whatever reason, you'll get most of them. Transfer to a breeding trap, and off you go!>
What is the shelf life of such chemicals?
<Good couple of years, at least.>
I ask because if I have any here it is several years old.
<Probably worth a shot, provided it was kept somewhere cool and dark.>
Please forgive me if I have demonstrated a lack of thought as it is quite late tonight and I have been taken aback by the sudden prospect of kittens.
Thank you for your wonderful site, Rose
<Baby Corydoras are fun to rear and highly entertaining. First time around you may lose a lot of them through various things, like not enough food, but you'll likely rear enough to make the whole thing well worthwhile. Good luck, Neale.> 
Re Corydoras Eggs 9/30/09

Hello Neale,
I would send this as a reply, but I didn't get an email but rather saw my question in the dailies. This morning I found more eggs (at least as many as the other batch), this time on the opposite end of the tank down at the floor in what I would call the Blackskirt Tetra danger area.
<I see.>
So far they have not been eaten and since I have read your answer I am going to go and buy a breeder net.
<Good stuff.>
From what I read here
I thought I shouldn't add Methylene blue to the main tank so now that I have two batches of eggs would you still recommend that I put them all in a breeder net, or would you say that I should put half in to another tank and treat them?
<Whichever is most convenient. The good thing with fish is they spawn again and again, often only a few weeks in between times. So you can experiment.
If something doesn't work, next month try something else...>
I think the eggs at the top won't be hard to remove and catch since I will have gravity on my side, but the other ones might be a bigger challenge for me. Thank you for answering my questions so quickly, Rose
<Good luck, Neale.>
Re: Corydoras eggs  11/22/09

Dear Neale / Crew,
<Hello again Rose,>
If you don't mind my sharing, I'd like to report on my Cory fry for others like myself that can't find much in the way of beginner stories.
<By all means, share away.>
So, continuing from my other posts, when I moved the small Corys from the breeder net and into the larger tank I counted 74, and this was 40 days since the 120 eggs were first discovered. The filter intakes were covered with pantyhose so they wouldn't get sucked up and they all seemed to be active and finding their food.
Despite daily partial water changes, the next couple days I found a few dead (various sizes, not just runts) and there must have been many more dead eaten by their peers in the next days as there now seems to be only thirty-some (of varying sizes) that seem to be holding steady.
<This does happen. Breeders wanting lots of juveniles tend to keep the fry in a big tank with no substrate. In standard community tanks, the substrate at the bottom of the tank is enough to harbour bacteria that seem lethal to small fry. For casual aquarists, this is no big deal, since the fun is simply raising a few fry, rather than hundreds. But if you're serious and want to sell the fry, then a tank where you can siphon out dirt from the bottom pane of glass daily seems to be important.>
Back in the original main tank, 40 days after they had the first eggs, the adult Corys had more eggs (over 170) that stayed on the wall for five days until I assume they hatched and were eaten. I guess the parents and the Blackskirts didn't have a taste for eggs?
On a side note, today one of the plump Blackskirts has been in a homemade cocohut all day and I have never seen them go in there (the huts are for the Corys). The fish's body looks normal, but I do wonder what it is doing (I assume NOT laying eggs as I have read that they scatter them carelessly).
<Blackskirt tetras (Gymnocorymbus ternetzi) are not the most peaceful tetras in the hobby, and in insufficient numbers can become nippy and waspish. Observe for a few days, and see if this fish is being bullied by its peers, or conversely, is behaving aggressively itself.>
Thank you, Rose
<Cheers, Neale.>
Re: Corydoras eggs 11/22/09

Dear Neale,
<Hello again Rose,>
Thank you for the response today in the dailies.
<My pleasure.>
I should have mentioned that the tank I moved the Cory fry into IS bare bottom for now, because I thought it would be easy for me to spot any dead as they would disappear over the beige sand that I use.
<Very good.>
I didn't know about the potential for substrate to harbor bacteria that could hurt them.
<Seems to be the case. The flip side is that a tank with lots of algae and Protozoans also contains lots of food that newly-hatched fish can eat.
That's what baby fish would eat in the wild. I recently bred some gobies while I was on the other side of the world, simply because the eggs hatched in a tank filled with algae, and the baby gobies found enough to eat.
Indeed, with livebearers, this is the best approach to take. But for whatever reason, Corydoras do seem very sensitive to microbes at the bottom of the tank.>
There are still more than a quarter from the eggs surviving at 56 days in and I take comfort in believing they would fare much worse than that in the wild.
<Heavens, you're doing much better than the wild! One of my marine biology instructors discussed Herrings, which have to spawn within a two-week period of time they can't accurately predict. Too early, there's no zooplankton for the Herring fry to eat; too late, and the population of algae in the plankton are so high they produce toxins that kill the baby fish. Some years no fry will survive, despite the female Herrings producing hundreds of thousands of eggs that season!>
I had mentioned a Blackskirt in the other tank that is hiding in a cocohut.
It is still there after at least 27 hours and has missed feedings.
<Odd. It might be ill, especially given its still not eating. Any other symptoms? Does it look swollen? Are its colours different to the others?
Are its fins raggedy?>
It is one of seven and none of the others are larger (I think it has reached full size).
<A good number... they should be happy.>
When they charge and nip they have always seemed to do so evenly and they are darker than many photos of their kind (even over beige sand).
<As is their wont. These are "boisterous" fish by any standards. If there's space, adding 2-3 more might help if the issue is social. But I'm not sure that it is.>
I'm surprised they don't nip at the Cory Cats as the Cats nearly blunder into them.
<Interesting. Corydoras are always nipped when I mix them with South American Puffers.>
Thank you, Rose
<Cheers, Neale.>
Corydoras Eggs, feuding Blackskirts 11/22/09

Dear Neale,
Sorry to bother you again, but wanted to say the Blackskirt finally came out of the cocohut and was being chased behind the heater and all over the place.
<By the other Blackskirt tetras? Does sound social, in which case adding more can help. But if they're picking on a weak or sick specimen -- as sometimes happens -- this might not work. You could try moving it to another tank. By itself it might swim about more readily, and if you're lucky, it won't be nippy.>
When the juvenile Cory Cats grow larger I was going to move some of them in with their parents and these Blackskirts so there was already going to be some fish shuffling going on. I am wondering now if I will have to so some dividing and reintroducing of these Blackskirts as I guess the odd fish out would not be happy kept all alone either, correct?
<It isn't ideal, but it is what I'd do.>
Thank you, Rose
<Cheers, Neale.>
Re: Corydoras Eggs 2/12/10

Dear Neale,
Since I have two batches of fry, one about twenty weeks old now and the other about ten weeks, I have a silly question. They are all different sizes. For example, one of the younger fry is the size of fry that are twice his age. I have only five all together and some of them graduated into the main tank about four weeks ago. Are their prospects of surviving with adult fish determined strictly by their size, or should their age also be considered due to mental development, etc.?
<Strictly determined by size. After about three months, or once they're about 2.5 cm/1 inch long, they can be trusted with adults, assuming the tank isn't too deep (remember, they're air-breathing catfish) and they can get some food.>
Thank you, Rose
<Cheers, Neale.> 

Population Control - Platies and Corydoras
Hi! Hope all is well with the crew members!
I discovered what I believe are a handful of Peppered Corydoras (maybe Albino Corydoras, they are clearish/grey at this stage) fry in my tank tonight.
<Well done! Peppered Corydoras and Albino Corydoras are the same species, usually, Corydoras paleatus.>
After getting really excited, I've turned to a state of worry about the rapidly increasing population. I was under the impression that Corydoras were not that easy to get to spawn?
<My Peppered Corydoras spawn all the time. So no, not that difficult. Other Corydoras species are much more difficult to breed, and some have not yet been bred in captivity. So it all depends, really!>
I certainly haven't been trying after I realized I had enough babies on my hands with the Platy fry. These certainly don't look like my Platy fry usually do, although I do have one bluish/grey Platy (but she is currently
pregnant in my opinion). They don't necessarily look like my Corydoras either, but more so than they resemble a Platy. They are also hanging out in caves and on the floor of the tank.
<That does sound more like Corydoras than Platies.>
In my experience, the Platy fry usually prefer the floating plants up top and would venture out occasionally mid and top level. But then again, I didn't notice any eggs in my tank either.
<Corydoras eggs are usually stuck to the glass and plant leaves, often halfway up the sides of the tank.>
Obviously, I have no real clue who these guys belong to. I am new to all of this (going on four months now) and my current 40 gallon tank that houses the Corydoras and Platies is currently recycling (after a medication attempt and misunderstanding about how long I could turn off my filters).
It seems I am prone to make every available mistake possible in this hobby, so I am still having to do daily large water changes as my ammonia and nitrites are spiking. Anywho, my point is, if even my Corydoras are having kiddos in such a unstable environment, what will the reproduction rate be like when I get everything squared away with water quality?
<Likely similar; in fact, the water changes are a key trigger for Corydoras breeding, because cold water replicates rainfall, which is what makes these catfish frisky!>
I'm having visions of tanks in every corner of my house and as cool as the fish/fry are, I'm not digging that idea.
<I wouldn't worry about it.>
Can you advise my best bet in controlling my population? I've read you can resell them to local LFS, however I would prefer not to do so if I can avoid it as I'm not comfortable with how I see them treat their Bettas.
<Do try posting on forums, such as the one we have here at WWM, or any other that appeals. Most have a "sale/swap" thread, and if you chat with people online, you'll be able to figure out who is a good fishkeeper and who is not. From there, you can offer up baby fish as freebies.
Alternatively, just leave them in the tank. Without specific care, few will reach even an inch in length, at which point they might just start to have an impact on filtration capacity. Thirdly, you can always euthanise fry as you see them. Fourthly, you can observe the tank carefully, and when you see eggs, remove them.>
I recently boycotted any LFS that sells Bettas in a cup and/or tinny tiny bowls. Maybe I should revisit this policy as it seems every store does this?
<Pretty much yes.>
And also, from what I've read, inbreeding isn't a good idea either.
<It's not a great idea, no, you do tend to get a lot of fish with genetic abnormalities such as crooked spines or small size.>
Can you suggest a plan of action for me? Maybe another type of fish that would help keep the fry population down? My PH is usually right at 7.6 and temperature steady at 75 degrees. Any other humane ideas (I'm not even sure adding predators is considered humane)?
<Adding egg-eaters is surely humane; Bristlenose catfish for example should do this rather well.>
I hope this wasn't a stupid question.
Thanks in advance,
<Well done, anyway! Cheers, Neale.>

Corydoras, repro.  07/28/2008 hi there, About a week ago my albino Corydoras were laying eggs and I was able to harvest some. They hatched by now and are still living off their yolk sacs. It seems a couple of them got stuck in their egg shells with their tails poking out. Can I do something to help them to get out? I am afraid that they might eventually suffocate. <You can gently roll the eggs about a bit with your fingers, or better still, squirt them with a pipette. But the "kittens" should find their way out eventually.> They are in a little container that floats on top of the main tank where the parents are living in a community with other fish. I do water changes once daily with the water from the main tank. I have done this before but never had the problem of fry stuck in the shells. <Does sometimes happen, and usually the fish come out fine.> Thanks for your help Silvia <Good luck with the babies! Cheers, Neale.>

Re: Corydoras, repro.  7/30/08 hi Neale, thanks for that. three of the four came out soon after I got your answer but the other one was stuck longer. I was afraid to roll the egg in case I could damage the little guy inside. the other problem was that there was still an empty shell stuck to it. I tried to squirt water into the empty shell which gave the little one a bad roller coaster ride but later it came out on its own although it looks a bit disabled. I will see how it survives. thanks again Silvia <It's the nature of egg laying fish that some eggs won't develop properly. Such fish have evolved to produce lots of eggs to compensate for the low chances of survival for each egg. You will likely lose quite a few fry over the next few weeks for various reasons; unless you're a serious breeder I wouldn't worry too much. Even if only one or two survive per batch, that's rather better than would happen in the wild! Good luck with the kittens, Neale.>

Re: Corydoras   7/31/08 hi Neale, one or two sounds really very little to me. <That's how Mother Nature works. If a pair of Corydoras produced more than a couple of fry that reached maturity, we'd be knee-deep in them pretty darn fast. Darwin worked this out using elephants. He showed that even allowing for the fact elephants breed extremely slowly, if every baby elephant survived, there'd be 15 million elephants within 500 years. I'm not saying you should aim for this with your breeding projects, merely resigning you to the fact that not every single baby fish can or will survive, and in the big scheme of things it doesn't matter.> as I mentioned before I have done it before, I just didn't encounter this sort of problem before. usually I have about a survival rate of 75% after hatching for the Corys. this time I lost already about 60% of the eggs before hatching. <Many things may be happening here. Fertility declines with age in many species, and inbreeding also reduces fertility. So if you're crossing siblings for example, you can't expect to have as many fry, or as many viable fry, as you would were you crossing unrelated wild-caught fish. Diet and water chemistry may be factors as well.> when I started harvesting the eggs the female was already laying eggs for some 4 hours and was already pretty exhausted. the earlier laid eggs were already eaten by the rest of the community. that's life :) <Yep, that's how my Corydoras breed, and the pufferfish follow them around snapping up the eggs like popcorn. I'm lucky if I rescue half a dozen.> I assume that some haven't been properly fertilized and some didn't develop right for one reason or another. <Could well be, but see above.> even after so many times I always find it amazing to watch the fish lay eggs, and than those ones not been eaten, to hatch and grow. much better than TV :) <Would tend to agree, being a person who doesn't have a TV set but does have three aquaria and a pond!> cheers Silvia <Please do write with capital letters in the right places next time. Normally we send messages back for re-typing if they don't. But I was feeling nice. Anyway, good luck, Neale.>

Re: Corydoras 8/2/08 Hi Neale, Sorry about the capitals. It's just a habit. A bad one I have to admit but thanks for being nice :) <No problem.> Good old Charles was right with a pair just to be replaced with a pair. In theory that is. <Ah, he was simply making the point that without predation, disease, competition, starvation, etc. populations of any organism have the potential to increase exponentially. What he wanted to make clear is that something happens that prevents this, what he called the 'struggle for life'.> In reality it doesn't work like this since homo sapiens has it's hand in it. We seem to be able to wipe out many species, sometimes before we even discover them. Most of that due to irresponsibility, disrespect and out of ignorance. The Australian Government introduced Gambusia into the river systems to control mosquitoes, ignoring that we have the best mozzie control already with our beautiful rainbowfish. It has devastating effects on all native wildlife. When we are going out to do surveys of the creeks and rivers we sometimes find bodies of water only with alien, non native fish. We means members of ANGFA (Australian and New Guinea Fish Association, check out our website www.angfa.org.au) . The other end of the scale are people who keep or release predatory animals into an environment that they are not native to. My garden is abundant with wildlife but I often fear for them because my neighbour is not willing to keep her cat inside. Cats are introduced to Australia and I keep mine inside all the time. <I know a few people who are in ANGFA, and they do sterling work. Bruce Hansen wrote an excellent chapter on Aussie fishes for my Brackish book. I'm glad you keep your cat indoors. As a cat lover, I've always felt guilty about the death toll cats inflict on wild birds. They are Nature's perfect killing machines, and in environments without predators and competitors, they can (and usually do) cause major problems.> Back to the Corys. Being a scientist I am happy having more than two surviving which might help to keep the wild population survive. Especially since specimens in captivity don't have the life span they could have. I remember a friend buying a sterbai because she liked him. I tried to point out that he needed company but she thought he was fine since he came out feeding. <Sad.> I showed her my Corys who are all over the place during the day but it didn't make a difference. She only had him for some nine month. Mine are now about five years old and still happy. The female albino looks like she is fattening up again only after two week since she laid eggs. The kittens are doing fine. Using the word kitten is very unusual for me. I know that the English and the Americans are using it but if I use it here I get weird looks. <What else you call a baby cat but a kitten?> Cheers Silvia <Cheers, Neale.>
Re: Corydoras... larger issues...   8/5/08
Hi Neale, <Silvia,> I am probably not the average person. I read Darwin but I don't own it. But that was some 30 years ago and I noticed that I often read things others wouldn't and don't read what they would. I am a geologist but haven't worked in the field. You could say "conflict of interest". I didn't want to be in a position where, say, I had to sign off on a big dam from a geology point of view and disagree because very old historical heritage would be destroyed or a habitat for fauna or flora. Initially I wanted to do ethology but the lecturer put me off when he came in with a bucket full of baby sharks for dissecting. I was not keen on that part anyway but when he said that they are ONLY sharks I lost it. I happen to love sharks, so that was the end of it. <Too bad. It's a common problem at university that you get exposed to science through the interests (or biases!) of the lecturers. Where I did my zoology degree most of the people studying invertebrates were doing so from the perspective of invertebrate pests and parasites. I got so cross with the lack of balance I ended up complaining to the head of department! But the reality is that most invertebrate biology is done from precisely those aspects. Most of the money in insect research is in pesticide development or malaria transmission or whatever. Most of the people studying nematodes are parasitologists, and so on.> I worked for an environmental organization I helped to found after I left uni. Due to various reasons we moved to Australia some ten years ago. And here is where I can make you again jealous, not really on purpose though. We live about 20 minutes away from the beach. So I have good access to estuaries and mangroves but I can assure you crocs are not a problem down here. The Gold Coast, that's where we are, has a lot of canal frontage developments and they attract bull sharks. I wouldn't want to mess with them, though. We didn't choose this area on purpose. My husband just happened to get a job here. <I'd tend to treat Bull Sharks with a certain degree of caution, too! They do of course swim into completely freshwater habitats, and likely account for most shark attacks in rivers.> I was never involved in fish keeping till my children joined the science club a teacher offered after hours. I joined as well in the hope to train my English skills. It turned out that the teacher was not very knowledgeable. She asked the children one day to bring in an empty 2l (~1/2 gallon) juice bottle to make an aquarium. She supplied the sand, the weed and the fish. I can't remember what the weed was but the fish she identified as guppy. Her recommendation was that they can find more in the drains or to release it once they don't want it anymore. I got a book about the wildlife around this area and identified the fish as Gambusia. Little did I know about the laws. Later we went fishing with the kids under a nearby bridge where the river is close to the sea which means it is brackish. <A-ha! Brackish water is often superb for catching small fish because so many marine fish lay their eggs there, or spend their first few months there as juveniles.> We found tiny Monos and scats which we kept. Unfortunately we kept predatory "shrimps" with them. I later brought the Monos to a pet shop because they outgrow the tiny tank and I had no idea how to create a brackish water system. The guy from the pet shop sold them in his marine section. At that time, when I started to explore fish shops, I was taken by the tropicals around. You hardly find natives in the shops and often only in the feeder fish section. <!!!> It seems people are more drawn to the "exotic" ones. Ours are only exotic to others. But I have to agree what we have in our rivers here is amazing and can match any South American or Asian. But isn't it that the average people want a piece of exotic in their living room, like an exotic place where they would go on their holiday? My experience is that people often don't appreciate what they have around mostly because they don't know any better. <I would agree with this. There's also legal complexity, making it difficult for someone who is inexpert to know where they can catch their fish or which species they can keep. Simply finding habitats with small fish isn't always easy, and then you have the problem of identifying the fish and obtaining information about their diet, social behaviour, etc. But on balance, I do agree that it is somewhat bizarre how little native fish are appreciated in many countries. Here in the UK we have a lovely diversity of marine fish and invertebrates thanks to the confluence of cold and warm water currents. We even have seahorses! And yet people very rarely keep British marine species in aquaria.> We didn't go for holidays for years. After I joined ANGFA we started do go to the field trips and it is a very nice holiday for us. We are together with nice people, go to places where we wouldn't go otherwise and see nice environments. For us these are exotic places, too. Another field trip is coming up in two weeks and I am looking forward to it. <Cool.> I love to have the geckos in the house because they take care of the cockroaches. "Natural pesticides". I don't like to spray with the fish tank around and I don't like to do it outside neither. I use the weeds to feed the guinea pig. My experience with Ancistrus is that I have a much better output when I leave him to do the work rather than hatch the eggs without him. <Broadly yes, when fish are left to rear their eggs, they tend to do a very good job, oxygenating them and removing fungused ones more delicately than we can manage. There are some species though where inbreeding has short-circuited this, most notably Angelfish.> Cheers Silvia <Cheers, Neale.>

Cory eggs...are they viable? - 7/2/08 Hi there! Neale, if it's you, I'll be delighted, because this is an offshoot from a conversation we had a little while ago. You had given me some fabulous advice (as usual!) regarding keeping golden wonder killifish with platys and Corydoras without a heater. Thanks so much for that. <It is indeed me; hello again!> I haven't yet gotten any new fish, except that I did move four of my bronze Corydoras from another tank to this new tank, so they could be one happy bunch (six in total, four C. aeneus. and one C. metae and one C. julii). Well, it seems they are happy indeed, because to my surprise, when I turned the tank light on this morning, I saw eggs! Not to mention a bunch of frolicking Cory cats, which they have been doing since the morning after I moved them all. What I interpreted as playfulness, must have been spawning behavior...although I have to say, I have not done anything particularly special for them. They've been eating meaty sinking pellets, veggie wafers, and some sinking foods like Aquadine crisps and New Life Spectrum pellets. I am not sure if it they are eating the bits of Nori I am giving them (or if it's the Malaysian trumpet snails making it disappear) but it gets offered about three times a week. <All sounds good. Corydoras do indeed spawn in the morning, and if they're happy, many species will spawn in the community tank.> I have also been changing 5 gallons of water twice a week. It's a 29 gallon tank, and the temperature is between 77-80 degrees, as this is what the house is. The water parameters are: Ammonia - 0 ppm Nitrite - 0 ppm Nitrate - <10 ppm pH - ~7.8 alkalinity - 300 ppm hardness - between 150-300 ppm (sorry, it's a strip) <All sounds fine for Corydoras.> I have re-read your article about breeding Corydoras paleatus, as I was especially interested in seeing a picture of the eggs. Everything I've read says that viable eggs are amber, and when they are white, they are no good. Certainly your C. paleatus looked amber, as I would expect. Well, these eggs are definitely white - but they seem soft and supple, not hard and crusty, like the gold ram eggs from a few years back, that I remember that were not viable. <The eggs start off white when laid, whether fertilised or not. Over the next day or so, they change colour. Fertilised eggs become greyish. Unfertilised eggs stay white. Moreover, after a few days the unfertilised ones become covered with fungus threads and need to be removed (a small pipette or syringe is ideal). Also remember the eggs are VERY soft immediately after laying, and it takes a few hours before they become hard enough to roll off the glass and into a floating breed trap or whatever (I use small plastic cartons with holes drilled into them for water to flow in and out).> To further add to my confusion, the posts that I have read on various forums have had pictures of eggs that look white, just like mine, but these seemed to have hatched successfully. <Don't worry too much about the colour; just remove them all as soon as you can, and then remove fungused ones as you go along.> I have a hopeless camera with a broken LCD (but I can't bear to throw it away, as I spent way too much on it before it broke!) so I cannot get sharp pictures, as I am shooting blindly without an ability to adjust the settings much. The picture I included was about the best I could do. <Looks quite normal to me.> Can you tell from the picture if these eggs are "still good"? I have not observed them eating them, although I am guessing that Corydoras are not much for egg eating. <Not sure the Corydoras will eat the eggs, but some snails will (not sure if Melanoides do) and certainly most other fish eat them.> Naturally, I would love to see some kittens...as you have said, they are sickeningly cute! I have a feeling this time isn't going to be "it", but if you have any additional tips for conditioning them and rearing them, I would be all ears. Going by your article, it seems I will know in a few days whether these eggs were viable or not, but of course, I can hardly stand the wait. <All else being equal, by the time you read this message it should already have become clear which eggs were fertilised and which were not. It's a bit of trial and error really, but Corydoras lay eggs every couple of weeks if you let them, and before long you will have more kittens than you know what to do with!> Thank you ever so much in advance! I can honestly say, I don't know what I would do without WWM. As Sinead O'Connor once sung, "Nothing compares..." Yours truly, Nicole <Thanks for the kind words! Neale.>

Cory fry, reading   12/18/07 Hi WWM crew love your site and work and all your help in the past, if this is Neale I'm sorry for being grumpy to you =\. <He's out for a few days... I'm REALLY missing him this AM> I was cleaning my gravel and everything was going normal when I suddenly panicked when I saw about 8 day old Cory fry. UGH. I wonder how many I kind of you know =\. Oh well so my next hour I spent rescuing fry. <Rescued?> I get eggs all the time usually from my two female albino Corys and my 1 male peppered Cory. Yes they do cross with each other during breeding. Hehe. Well, I only rescued 3 = ( so that made me sad but they are doing fine eating finally crushed flake and such. They are in a container with a bubble maker in with them. Well, I compared all 3 to pictures 2 of them look like baby peppered...but one looks like an albino with some spots. Do I have a hybrid? not sure but will they be fine with this diet and containment? <... is likely a cross... maybe w/in the same species though... Please read here: http://wetwebmedia.com/FWSubWebIndex/armcatreprofaqs.htm and the linked files above. Bob Fenner>

... Corydoras repro... algae/"mold" poor English   12/16/07 hi WWM crew I've been keeping my tank maintained perfectly, its a 25 gallon community tank. but last week I noticed a lot of mold on the bottom so I started cleaning it and I got a snail. this week I noticed even more mold growing on the bottom. so I started cleaning it and I saw baby Cory catfish -.- just my luck probably sucked up a fee of them. so now what can I do to get rid of the mold and keep the babies safe, I probably have about 10 babies also I noticed some small worms wiggling around every once in awhile and fish eating them. Mmmmm? thanks for your help <Greetings. Assuming these are something easy to rear like Corydoras aeneus or Corydoras paleatus, your best bet is to move the fry to a floating breeding net/trap for the first month or so, and then to another tank. Corydoras fry grow quite slowly, but after about 2-3 months they are safely mixed with their parents. Cheers, Neale.>
... Corydoras repro... algae/"mold" poor English... bad to worse   12/16/07
this doesn't answer my question, what's going on with my tank? whys the mold growing and how do I get rid of it? and I cant move the babies since they are good hiders and they are big enough to be with their parents. <Feel free to say "thanks" and extend common courtesies such as using proper spellings, grammar, capital letters, etc. Certainly avoid taking the attitude that you paid for my services and I didn't deliver. The "house rules" for messages to WWM crew are on clearly posted on the FAQ address page, so there's really no excuse for not making an effort to be polite. Your bad manners dealt with, let's turn to your fishkeeping skills. Mould grows in dirty tanks and can't grow in clean tanks. Period. End of discussion. Moulds can't grow on clean gravel or bare glass because they can't find anything to eat there. If your aquarium truly has fungi growing along the bottom of the tank, then you have a lot of organic detritus there for them to eat. So clean and/or replace the substrate and keep in clean as part of your normal maintenance regime. Dirty tanks lead to high rates of fry mortality. When rearing fry "the cleaner, the better". Cheers, Neale.>

My Corys... repro.   11/12/07 Hi. Something just amazing happened, I was watching my new Pleco when I glanced at my Corys and they were in the T position. this is normal because I get eggs all the time and they never hatch, but this is the female that doesn't give eggs. What was weird was the male is a pepper Cory and the female an albino, Is this common? Also I am watching the female and she hasn't put out any eggs, how long does it take for her to give eggs? Or was she just pleasing the male because he is ALWAYS following her around. <Depends on what sort of albino Corydoras you have. Most of the albinos traded are Corydoras paleatus, but some are Corydoras aeneus. Hybridisation between Corydoras species is rare. But if the albino Corydoras is C. paleatus, and the male is C. paleatus, they could potentially breed, in which case the offspring will be regular, not albino, catfish. As for hatching the eggs, this shouldn't be difficult. Be sure and read this: http://www.wetwebmedia.com/FWSubWebIndex/coryreproart.htm . Cheers, Neale>

Hello, I was wondering if you could tell me what I would need to breed Corydoras barbatus.   12/27/06 CJ <In a general sense/way yes. Please read here: http://www.wetwebmedia.com/FWSubWebIndex/callichthyids.htm and the linked files above. You would do well to further look into (the Net, libraries) books on Callichthyid Catfishes... David Sands works are especially notable. Bob Fenner>

Albino Cory catfish   12/8/06 Hi.  I have been searching everywhere for some pictures or a detailed description of just what a freshly hatched albino Cory catfish looks like.  Do they kind of crawl around on the glass for a little while before they start swimming? <Mmm, not on the glass... eggs might well be laid there... wiggle, freely once hatched out... on the bottom... in slight depressions, in a grouping...> I hope you can help!!!  Thank you for your time.                                Lyndi <Have seen such images in books on Callichthyids, Corydoras species... If you are seeing something crawling on the glass... it's not a catfish. Bob Fenner> Re: albino Cory catfish (second attempt to respond) <Thanks Tom>   12/9/06 <<Hi, Lyndi. Tom>> There was no answer to my question. <<Ill try to re-post Bobs response for you>> Albino Cory catfish   Hi. I have been searching everywhere for some pictures or a detailed description of just what a freshly hatched albino Cory catfish looks like.  Do they kind of crawl around on the glass for a little while before they start swimming?   <Mmm, not on the glass...wiggle, freely once hatched out...on the bottom...in slight depressions, in a grouping...>   I hope you can help!!!   Thank you for your time.                                  Lyndi   <Have seen such images in books on Callichthyids, Corydoras species...If you are seeing something on the glass...it's not a catfish. Bob Fenner> <<Tom here again. Do a Google search (Images) for 'Albino Corydoras fry', Lyndi. Scotcat.com has a nice image of these. (Would have included the link for you but it was too long to fit in this format.) Hopefully, this will find its way to you this time.>> Lyndi <<Tom>>

Catfish egg-release; dwarf Gourami mouth illness/injury   10/27/06   I am sorry if this is a repeat, but I can't remember if I already sent it. <Well, I've not seen it before, and if it was responded to, you've had received an e-mail...> Hello WWM crew. <Hello!> Your website is an incredibly useful resource, and I have used it on multiple occasions. <Excellent - that's what it is here for!> I have a 20g community aquarium. I thought it would have been done cycling months ago, but the ph is very low. <pH isn't affected by cycling - establishing the nitrogen cycle refers to a spike, then respective decline, in ammonia, nitrite and nitrate...read here for add'l info.:  http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm > I have a pair of platies, a pair of guppies, a pair of zebra Danios, a male dwarf Gourami, and a Corydoras catfish. Because of all the pairs, I also now have about 20 mixed livebearer fry. <Yes, this will certainly happen!> I also have a small amount of aquarium salt, and recently did a water change to help raise the ph. I realize now that the salt and jump in pH (about 5-6)... > 5.0 to 6.0, you mean?! That's a *huge* swing...too much for any fish to handle well. With regards to the aquarium salt, when you say "very little", I assume you dosed according to directions? Presuming this, the catfish (nor anyone else) should be harmed.  It's the pH that worries me...> ...could have easily killed the catfish, but instead, this morning I found about a dozen (the number has since decreased) small white eggs stuck to the filter tube, glass, and on various parts of my Swordplant. <Likely due to stress from the huge change in pH...> I am absolutely positive that there was NO male involved. <It's possible.> The conditions were hardly favorable, I did nothing to trigger spawning... <You actually did - by adjusting the pH so quickly, you stressed your livestock out...could have killed them...> ...though there may have been unintentional conditioning as all my fish have been on a diet of Tetra® flakes, frozen bloodworms, mall earthworms, and live baby brine shrimp (the ones that escaped the fry, that is, whose motto seems to be "eat until you can't swim, and then eat whatever swims to you". <Little piggies!!> I know that it is impossible that the eggs got fertilized, so why did she lay them? Is this normal? Could it hurt her? <The release of eggs itself won't hurt the fish, but as stated above, the large swing in pH could.  Stability in pH (as in temperature) is more important than precision, although 5.0 is very low.  I suggest you look into a product like Aquarium Pharmaceuticals "pH Adjust", add it to your water *prior* to doing a water change, then *very slowly* raise the pH by doing water changes (no more than .01 or so per day. Are you using tap water, or de-ionized or reverse-osmosis/de-ionized water? I use RO/DI, and a 5.0 pH is what the unit makes water at.  Either way, since your pH is this low, I would suggest using a quality supplement to increase it, as described above.  Kent also makes a quality product to accomplish this.> Any feedback would be greatly appreciated. John O. <Hope I've helped.> P.S. One more question: (that is somewhat irrelevant but of equal, if not more importance.) <Shoot!> My male dwarf Gourami has something terribly wrong with his mouth. For a long time, his top lip was swelling up, but he didn't act any differently, so I thought it was nothing. A chunk of the swelling actually came off, and the rest of his mouth is inflamed, falling apart, and growing strange puffy things. He hides a lot and does not make the usual clicking noise when he bites, it is now rather muted  I thought it could have been a number of things: the first thing I thought of was mouth rot, but I didn't want to medicate unnecessarily and endanger the lives of the other inhabitants, or kill off all the plants which have FINALLY rooted. Please help me. I would like to know - 1. What is wrong with my Gourami? <Could be mouth rot, mouth fungus, Lymphocystis (that's my hunch based on your description).  First off, you should isolate this fish into a separate quarantine/hospital tank - you don't want him to pass this along to other inhabitants.> 2. What medication should be used? <If it is Lymphocystis, you can't truly cure it, as it is viral in nature. However, based upon the lesion / "skin falling of" description, I'm concerned about secondary bacterial infections.  You must be sure to keep this fish's water *pristine*, and I'd suggest medicating (in the hospital tank only) with a broad spectrum antibiotic such as Spectrogram.> <NEVER medicate your main tank - this will kill your biological filtration and nitrogen cycle.  Once the Gourami is in QT, again, I think a broad spectrum antibiotic is in order.  Also, you may add MelaFix (along with the antibiotic) to promote regrowth of the fallen off area. 3. What can I do to alleviate the pH problem? <This is addressed above.  Also, the Gourami's immune system was also likely compromised due to the large pH fluctuations...you *must* ensure stability, as described earlier...> Any and all help will probably save a life. <I hope so - hopefully you've caught it in time!> Thanks in advance, John O. <You're welcome.  Hope I've helped.  Jorie>

Breeding Corys, reading   6/28/06 My son has a 10 gallon aquarium with Cory cats.  He has four adults, and we recently lost two due to problems with our filter and water.  The water problem has been fixed, but imagine my surprise when I started cleaning the tank and found a baby Cory cat, about a half an inch long.  We never intended on breeding the Corys, and we didn't even know what sexes we had. <Easy enough to do> I also don't know what the eggs might have looked like or if more will hatch. <Not hard to find...>   The baby is still in the tank with the adults, but should we separate it into a separate tank? <Not necessary> Do Corys usually cannibalize their young? <Sometimes eat eggs, very young, but often ideal parents> And should I expect more babies in the future. <With good care, decent water quality and nutrition, quite possibly. Do take a read on WWM re Corydoras Reproduction. The Google search tool... Bob Fenner>

Corydoras Breeding and Pleco Info  - 02/16/2006 Hi to all the crew at WWM. Thank you especially Mr. Bob Fenner for your advice on the swimming behaviour of my Mochokids. I just have a few other questions please. One of my bronze Corydoras has deposited about 70 eggs on the aquarium glass, will they be safe in the community tank or should I transfer them to the smaller quarantine tank that we have on permanent standby. If so how do I go about moving them safely? < The eggs are best in their own tank. Scape them off the glass with a single edged razor blade. Be sure to use water from the original tank. Add an antifungicide too.> Also I would like to acquire a lemon spotted green Pleco but am not sure if my tank is big enough (4ft) as I have heard some Pleco can grow to approx 18 inches is this the case with the lemon spotted green Pleco. Thank you. Ann < Go to planetcatfish.com and find the Pleco you are looking for. Common names sometimes mean different fish in different parts of the country. This is a great website that can tell you everything you need to know about your Pleco. The trick will be to match up the photos with the exact Pleco you have in mind.-Chuck>

Bronze Catfish disease, reproduction  02/12/06 Hi. I have six bronze cats which have are all happy and healthy. They play in groups in the bubbles and are very active. One of them laid eggs a couple of weeks ago and became very fat again looking like it was about to spawn but died very mysteriously. It was starting to look quite swollen and reddish around the lower belly. Has she died from not laying her eggs? Sorry to bother you but have tried Google with no luck. Thanks very much, Dave. <This fish might have been "egg-bound"... a condition where the eggs don't pass for a few possible reasons... or perhaps became infected in the area. Providing suitable water quality, nutrition avoids many of these incidents, but not all. Bob Fenner>

Pregnant Cory?  12/18/05 First, wishing you all Happy Holidays from Michigan (where there is no doubt of a 'White Christmas'!).    <And to all, peace on earth, good will toward all>   I have six Corydoras leopardus (Leopard Cory's) in a well-established, 50-gallon, community tank along with six Bloodfin tetras, six Black-skirt tetras, one Red Flame Gourami and four Serpae (Red Minor) tetras (will re-think this choice of animal in the future for a "community" FW venture).    <Okay>   The Corys are a particular favorite of mine and I spend a lot of time - inordinate, according to my wife - observing my fish, these especially. Tonight, one plunked himself/herself down on top of a decoration and "refused" to be moved. No labored breathing, parasitic "attachments", discoloration or outward damage/injury. Just wouldn't be budged by me or its tankmates, though some of the other Corys tried. (I've observed the occasional "pause" before in Corys but never on a prolonged basis.)    <What characters at times!>   Before making a panicked lurch for the QT, I reached in and gave the little fellow a shove. Off and, running, with no duplication of this behavior. Time will tell but is it possible that this is an indication of pregnancy? (I've never been a "grandparent" before. :) )      Thanks for your time, Tom <More likely "just dozing" or trying to capture your mind! Bob Fenner>

Fat Cory  11/30/05 Hi! I have a 15 gallon tank with a few goldfish and 2 albino Corys. My landlord rescued the Corys who were abandoned by a previous tenant and gave them to me. They've been living peacefully with the gold fish for many months now. I did notice that one Cory has grown very fat now, fat all around, yet it is still a small fish maybe 1 1/4" long. It's still been very active swimming and eating. Is it overeating or about to lay eggs? I haven't been able to find out what's wrong with it by researching on the internet. Do you know? Thanks! Lea <Corys will breed when given good conditions. If all else seems OK with them then your fish is probably gravid. Don> 

Corydoras arcuatus Hi WWM Crew :) Good day to you all. I have a question concerning Corydoras arcuatus. I've been trying to get my trio to breed and have tried everything I feed them bloodworms 3 times daily mixed with flakes and Tubifex worms. And I get up real early and do 50% water change with 60 degree water to induce spawning and nothing should I continue to do water changes till they spawn? There isn't too much info on spawning these my Corys are 1 1 1/4 inches. Thanks JM <Do check on the hardness of the water you're using for the changes, and make or buy or collect (as in rainwater) as soft a water (other than distilled) that you can here. Also, try not making the water changes for a week or so between two, three days of doing so, and augmenting their diet with more, different meaty foods. Bob Fenner>

Cory Eggs 2/24/04 <Hi, Pufferpunk here> I have a 20 gallon tank with 2 African Dwarf Frogs, 3 Black Skirt Tetras, 1 Scissorfin, 4 Corys and 3 shrimps. The tank is doing beautifully!!! So well that my Corys decided to spawn and have laid about 50 - 60 eggs in the tank. I adopted these Corys about 4 months ago and apparently they like their new digs very much. I love keeping a tank but I was not prepared for spawning and don't exactly know what to do now. I've read that they may eat the eggs and I understand that I only have about 5 days to decide before they hatch. Should I just leave them and take a chance on having live young, remove them or dispose of them? What do people do with the new fish? Sorry to be so naive about this...it's probably just a matter of me making a decision. <What I did, was scrape the eggs off the glass & put them in a breeder net, inside the tank. Not all the eggs hatched, but I did have many fry that I raised to adulthood. Try hooking the net across the output of your filter, so they will get fresh water. ~PP>

Cory cat eggs Hi all, We have a male and female CORYDORAS AENEUS who just laid eggs. We also have a weather loach in the tank who sees the eggs as food. <so will the parent Corys.> So what we did was gently removed the eggs from the glass and placed them in a floating breeder with an air stone because we read they need a lot of aeration. <Good idea!  Actually, I just hung the breeder net inside the tank.  I raised the fry in there, until they were large enough to release.  They ate crushed up flakes.> If you have any hints or suggestions they will be much appreciated. thanks <You're welcome & good luck w/your new babies--Pufferpunk>

Re: Eggs in Tank Well, as of last night, Thursday, there aren't any white spots! I will still hold off on cleaning, just in case. Robyn <If they were Cory eggs you may find the fry huddled under a rock or some other little cave on the bottom. Still think it's more likely the eggs or freshly hatched fry were eaten. Keep an eye out, but don't let the tank go too long Don>

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