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When I only had a smaller tank, I had a peppered corydoras female (C. paleatus) in with a panda corydoras male (C. panda). I was surprised to find eggs, as I never thought these two species could hybridize. I was even more surprised to find that the remaining eggs (after the corydoras and tetras snacked on some of them) were fertile. Imagine my surprise when some fry showed up in my tank!

I currently have two older fry in my 55 gallon tank, along with their parents and two albino bronze corydoras (C. aeneus). There are three younger fry remaining in the 10 gallon by themselves.

I have an image of one of the older fry. The bands from the panda are clearly visible, as well as the spots from the paleatus. This one appears to be a female.



Has anyone else successfully hybridized these species, or is it a new hybrid?

Hi Redfish,

I'm guessing you haven't come across the firey rants about hybrids on this site yet so I'll give you a little (okay, somewhat lengthy) rundown of what I learned this year;

Many people are trying to make sure hybrids aren't produced or sold because they could mess up true species. It could be a bit of a disaster for wild populations or rare -or undiscovered!- populations if any of these fish ever got crossed by someone who didn't know or if they were released into the wild. Some fish only exist in aquarium at the moment because their natural home has been wiped out of is pretty much a war zone, those fishkeepers go to great lengths to make sure the species stay true.

Sometimes it just happens by mistake but it may be best to take care that these fish never get passed on. Some people breed certain fancy fish for the aquarium trade but they are more like plants - the parents etc are tracked and traded with care and it's big money in many cases. On the other hand many catfish breeders have no ethics about damaging the bloodlines etc and are just greedy. If you look up the term hybrid on the search here, you'll get masses of info about why people are so outraged by it in most if not all cases.

Where I live almost every single synodontis I've ever seen is a hybrid
On the bright side, there's so many colours, styles, habitat types etc of catfishes that no one would ever really need to hybridize them on purpose. And there's new ones being discovered all the time - 9 of my favourites have been discovered in this century and there's many more.

I'm in the same boat as you in a way, I have a hybrid. Most people advised me to BBQ him but since it's not the fish's fault, I'm just going to let him live his life out without making any babies - or if he does and I don't catch it, there's lots in the tank to make sure the eggs get eaten.

It's a tough topic but don't take it personally if someone lets a rant fly. If you're sure your little dudes are hybrids, you may want to add and egg eater to the tank to make sure it doesn't happen again
Here's a good idea though...get your corys some matching partners Make new babies

Cheers
PS Don't mean to sound preachy but better to give you a heads up just in case someone pipes up screaming hellfire and brimstone about hybrids, it's a sensitive topic.

very interesting looking.

This is very interesting. I'd never have thought that paleatus would cross with panda. They are really very different in many ways.
It would be interesting to see if these fish were fertile.

mummymonkey wrote:It would be interesting to see if these fish were fertile.

Please, don't promote hybridyzing. If it happened in my tanks (I have both species, the tanks are not even in the same room ) I would destroy the eggs/fry, and only feed the remnants, in order to be certain nothing survives

wheter the h*****s are fertile or not, would be the least of my worries

Yeah, don't spread those. If fertile their offspring will be similar to one of the parent species, but will still be hybrid, and if you pass them on to new owners they'll get confused with the species they look like the most.

I don't think anyone wants a repeat with Corydoras of how it is with Synodontis, where pretty much all fish sold are hybrids and it's difficult to find actual species any more.

That's not to say hybrids can't be interesting. I accidentally hybridized Poecilia caucana with Limia nigrofasciata, and the resulting, highly fertile, fish had the good looks of the nigrofasciata and the peaceful disposition of the caucana.

Yeah, I don't plan to spread these on. It happened by accident and I'm not going to create more hybrids.

I also hate deliberately created hybrids, but I'm interested to see your accidental ones- the fish pictured is quite striking.

hybrids do occur in the wild though. I have to say I like the look of it.

RIPbiglad wrote:hybrids do occur in the wild though. I have to say I like the look of it.

Not really, in a general case, because if there is a crossover in native distribution, the species would not have separated in the first place. It's not impossible that there are species that cross in nature from human intervention (e.g. moving a species into a habitat where another species exist that can cross with the original species), but it's extremely rare that a species in nature will cross with another species. #

Yes, I'm aware that human pollution in Lake Victoria has caused hybridization, because the males and females can no longer distinguish their own species from other species.

--
Mats

MatsP wrote:

RIPbiglad wrote:hybrids do occur in the wild though. I have to say I like the look of it.

Not really, in a general case, because if there is a crossover in native distribution, the species would not have separated in the first place. It's not impossible that there are species that cross in nature from human intervention (e.g. moving a species into a habitat where another species exist that can cross with the original species), but it's extremely rare that a species in nature will cross with another species. #

Yes, I'm aware that human pollution in Lake Victoria has caused hybridization, because the males and females can no longer distinguish their own species from other species.

--
Mats

Actually, hybridisation is not that uncommon in the wild. There are numerous examples of hybrid zones. If i went outside now I don't think it would take me very long to find hybrid dock Rumex obtosifolius x R. crispus or hybrids between Southern marsh orchid and common spotted orchid. But anyway, things that don't co-occur in the wild can't hybridise naturally. I would also avoid the production of hybrid fish but if they occur accidentally i find it very interesting to see the result, especially if they are in the hands of a responsible fishkeeper who isn't going to spread them.

MatsP wrote:

RIPbiglad wrote:hybrids do occur in the wild though. I have to say I like the look of it.

Not really, in a general case, because if there is a crossover in native distribution, the species would not have separated in the first place. It's not impossible that there are species that cross in nature from human intervention (e.g. moving a species into a habitat where another species exist that can cross with the original species), but it's extremely rare that a species in nature will cross with another species. #

Yes, I'm aware that human pollution in Lake Victoria has caused hybridization, because the males and females can no longer distinguish their own species from other species.

--
Mats

I'm not sure I agree with this, for non-catfish, at least. Among Eurasian cyprinids, roach, rudd, and bream all hybridise naturally with each other, and evidence suggests there's also a low level of back-crossing in some populations. I also remember some research on the level of genetic difference between salmon populations spawning in different rivers, and the largest difference betweent he populations was due to the level of hybridisation with brown trout.

Carp37 wrote:

MatsP wrote:

RIPbiglad wrote:hybrids do occur in the wild though. I have to say I like the look of it.

Not really, in a general case, because if there is a crossover in native distribution, the species would not have separated in the first place. It's not impossible that there are species that cross in nature from human intervention (e.g. moving a species into a habitat where another species exist that can cross with the original species), but it's extremely rare that a species in nature will cross with another species. #

Yes, I'm aware that human pollution in Lake Victoria has caused hybridization, because the males and females can no longer distinguish their own species from other species.

--
Mats

I'm not sure I agree with this, for non-catfish, at least. Among Eurasian cyprinids, roach, rudd, and bream all hybridise naturally with each other, and evidence suggests there's also a low level of back-crossing in some populations. I also remember some research on the level of genetic difference between salmon populations spawning in different rivers, and the largest difference betweent he populations was due to the level of hybridisation with brown trout.

The same is witnessed in birds with small overlapping distributions, it helps with immunity to disease and genetic diversity when some of this goes on in the background to the two populations. This is a true minority of the time, depending on the event that this occurs in.

Have to admit that this particular instance of hybridization is a scientifically interesting case.

I know a lot more about trout and related Salmonid hybrids than I do about catfish hybrids except to say I am aware of the Synodontis mess and the artificially produced S.A. Pimelodid crosses. It is amazing how many instances there are of inter-generic hybrids. It's easier to under stand intra-generic hybrids occurring. It also demonstrates to what extent taxonomy is an artificial construct imposed to make sense of relationships between organisms which do not read journals.

apistomaster wrote:It also demonstrates to what extent taxonomy is an artificial construct imposed to make sense of relationships between organisms which do not read journals.

The only thing found in nature are species. All other groupings - genera, families etc - are at worst just grab-bags of species, or at best names given to the ancestral lineages of groups of species.

Hybridization is a primitive character, so that distantly related species hybridize doesn't really say anything except that neither of the species involved has mutated in such a way as to hinder reproduction with the other. As time progresses barriers to reproduction become progressively more likely to have formed, which is why hybrids between members of different higher taxonomical units are less common than hybrids between members of the same genus.

In nature most hybrids are selected against. This is most obvious when you have overlapping species with a narrow hybrid zone: that means that the hybrids have reduced viability or ability to reproduce. A typical example is the hybrid zone between the hooded crow and the carrion crow in Europe; there is a minute gene flow across the zone, but the hybrid offspring is heavily selected against. Reduced viability is probably also why species like roach and rudd remain distinct despite regularly hybridizing and producing fertile hybrids. If the hybrids are fully viable the two species would rapidly coalesce, as has happened with the red and the gray wolf in the USA.

Plants are a separate issue as they do all sorts of weird things.

Mike_Noren wrote:In nature most hybrids are selected against. This is most obvious when you have overlapping species with a narrow hybrid zone: that means that the hybrids have reduced viability or ability to reproduce. A typical example is the hybrid zone between the hooded crow and the carrion crow in Europe; there is a minute gene flow across the zone, but the hybrid offspring is heavily selected against. Reduced viability is probably also why species like roach and rudd remain distinct despite regularly hybridizing and producing fertile hybrids. If the hybrids are fully viable the two species would rapidly coalesce, as has happened with the red and the gray wolf in the USA.

I agree with Mike that hybrids MUST be selected against, otherwise species would merge. However, I remember a talk at the same Journal of Fish Biology conference in 1990 (I think), where they were looking at backcrosses of hybrid cyprinids (I'm assuming these were artificially fertilised), where fry survival (admittedly in the lab) was substantially greater for both hybrids and backcrosses, than for same species fry (roach-bream and rudd-bream showing particularly good survival rates). Unfortunately I think this talk didn't make the journal edition due to late submission, otherwise I'd have dug it out to confirm their results and search for related papers. The fact that this is lab survival and artifical fertilisation puts a few question marks over the validity of the results in the real (natural) world, but the findings were pretty surprising to me.

Another anecdotal (so of limited value) case: I fish the tidal River Trent a fair bit, and in the early to mid-1980s, roach-bream hybrids were the most prevalent fish to catch. Most of the matches I fished in summers during this period (where gross weight of fish caught, not number/size, determines results) were won with catches consisting largely of roach-bream hybrids (and most of the fish caught in the match would also be these). However, in the late 1980s the switching off of most of the coal-powered power stations which used the Trent for water cooling, reduced water temperature by a couple of degrees in summer (possibly slightly more in winter), plus an alleged improvement in water quality, saw these hybrid populations crash. Bream, carp, roach, chub, and bleak numbers also reduced markedly at this time, although barbel numbers increased exponentially (at least in terms of fish caught, which might not be the best measure of fish abundance). Roach-bream hybrids still occur in most waters where both species occur, but are normally (as expected) the exception rather than the norm. I've no idea why their numbers were so high during that period and don't know if it was temperature or water chemistry that gave them an apparent advantage.

I'm also assuming that most (though probably not all) hybrids are accidents of groups of different species spawning at the same site at the same time, which makes it all the more amazing that in certain conditions, hybrids can be so prevalent. I have wondered whether the fish, though fertile, might get a bit confused at spawning time- do they spawn with each other, or with one of their parent species? If the parent species have different spawning/gonad development triggers, how does that affect spawning? Whilst I'm fairly sure I've seen backcrossed fish (fish that look more like a bream than a typical roach-bream hybrid, or more like a roach), I've never been totally certain that's it's not just a slightly odd hybrid. However, despite the prevalence of hybrids (I've also seen a lot of natural carp-crucian carp hybrids, although they also produce these commercially for fisheries under the somewhat confusing term of "f1"), the number of presumed backcrossed fish I've seen is comparatively miniscule.

These thoughts you guys present about crossbreeding and hybrids are quite interesting, and makes me wonder if some of this could be relevant regarding the puzzling situation in Rio Xingu, Brazil with all the varieties of Hypancistrus found there. A relatively limited area of that river (the part closest to the Amazon itself) is home to a vast number of Hypancistrus (L46, L66, L174, L173, L236, L333, L399/400 plus several without an l-number) which just seems odd. But if some of these are pure species which occasionally cross with eachother, if the offspring is selected against in nature that could be a potential explanation as to why some of these varieties are much rarer than others. Just a thought

-Haakon