Are the different Pygmy Cory varieties able to interbreed?

[OliveFish05]

Are the three Pygmy Cory varieties (hastatus, pygmaeus, and habrosus) able to interbreed? I searched around a little bit on the internet but couldn’t find much about it, except one article saying “only keep one species of Cory, they can interbreed”. It just didn’t sound very accurate or legit. I am asking because I thought it would be very interesting to have a tank, maybe a 40 breeder, with all three Pygmy Cories varieties (and maybe some cherry shrimp) set up with breeding in mind (driftwood, Indian almond leaves, alder cones, sand substrate, sponge filters or hang on back with pre intake sponge, lots of plants like Anubias, amazon sword, cabomba, water sprite or water wisteria, frog bit and such). I of course don’t want a bunch of little mutt Cories, So thought I’d check if that’s even possible first!

Also a side question, will nerite snails eat Cory eggs?

 

[Essjay]

Some species of cory can interbreed, it depends on the lineage. Byron has told us that there are 9 different lineages and that cories in the same lineage canoften interbreed but those in different lineages are not likely to.
But I have no idea which lineage each of the three dwarf cory species are in. Byron and DoubleDutch may be able to tell you.

 

[Bruce Leyland-Jones]

I've never heard of them interbreeding, (I once kept hastatus and pygmaeus together, with no hassle. The pygmaeus bred and the offspring all at least appeared to be pygmaeus). That said, they are clearly related and it's more than possible that hybridisation can occur, as it does with their larger cousins.
I don't believe that the nerites will eat the eggs, but there would always be a risk of that large, muscular, snail foot causing some damage, if it was to go atop a bunch.

 

[Byron]

Here you are.

Corydoras pygmaeus and C. hastatus are in lineage 4 which also holds C. guapore, C. mamore, and C. paucerna. This lineage holds these five described species, and to date no undescribed "C" or "CW" species. This is a small lineage, but it is I think interesting in that two of the species are "dwarfs" while the other three are not. These two dwarfs are somewhat closely patterned and do behave very similarly, both certainly enjoy spending more time above the substrate and swimming with shoals of small characins than most if not all species of Corydoras, so it is perhaps not surprising that they are together. And this is one of the benefits of taxonomy...knowing that the species within the genus will share many physiological and behaviour traits.

C. habrosus is rather different from the other two "dwarfs," and is in lineage 9 which holds 162 species, 63 described and the remainder C or CW undescribed species. This "dwarf" is more cory-like than the other two dwarf species, if that makes sense.

Taxonomy involves the relationships of species, and those descended from the same ancestor species are classified in the same genus; when this occurs, it is deemed a monophyletic genus. The species in a genus therefore have the closest relationship and are more likely to hybridize. But this depends upon circumstances. Ian Fuller has noted that species within the same lineage that are maintained in decent-sized groups of each species are less likely to cross-breed because their natural instincts lead them to spawn with their own species if male and female are present. The hybridization is much more likely to occur if one species has only males or only females, and the other species in that lineage has the opposite gender. I have certainly had this occur in my tank of cories, where a female (on her own due to last survivor) has spawned with a male of another species which happened to be one of two males of that species in the tank. But you do not want to encourage this, so maintaining decent-sized groups (including male and female in numbers) of each species should prevent hybridization, though nothing is ever cut and dried.

In case you're wondering what "lineage" is all about, it has to do with evolution of a species. A lineage is a group of species that all descended from the same ancestor species, and the clade is termed monophyletic. The genus Corydoras is polyphyletic, which means that the species now classified in this genus descended from more than one ancestor. Nine lineages within the present genus have been identified, and no one doubts this because every phylogenetic analysis to date has confirmed it. Eventually there will be nine genera in the family; one will be Corydoras, but the vast majority of the 465 known species will be in a different genus from the true Corydoras species. Aspidoras is within this classification (lineage 2), and Scleromystax (lineage 3), and the three former Brochis species are in subclade 1 of lineage 8.

 

[OliveFish05]

Here you are.

Corydoras pygmaeus and C. hastatus are in lineage 4 which also holds C. guapore, C. mamore, and C. paucerna. This lineage holds these five described species, and to date no undescribed "C" or "CW" species. This is a small lineage, but it is I think interesting in that two of the species are "dwarfs" while the other three are not. These two dwarfs are somewhat closely patterned and do behave very similarly, both certainly enjoy spending more time above the substrate and swimming with shoals of small characins than most if not all species of Corydoras, so it is perhaps not surprising that they are together. And this is one of the benefits of taxonomy...knowing that the species within the genus will share many physiological and behaviour traits.

C. habrosus is rather different from the other two "dwarfs," and is in lineage 9 which holds 162 species, 63 described and the remainder C or CW undescribed species. This "dwarf" is more cory-like than the other two dwarf species, if that makes sense.

Taxonomy involves the relationships of species, and those descended from the same ancestor species are classified in the same genus; when this occurs, it is deemed a monophyletic genus. The species in a genus therefore have the closest relationship and are more likely to hybridize. But this depends upon circumstances. Ian Fuller has noted that species within the same lineage that are maintained in decent-sized groups of each species are less likely to cross-breed because their natural instincts lead them to spawn with their own species if male and female are present. The hybridization is much more likely to occur if one species has only males or only females, and the other species in that lineage has the opposite gender. I have certainly had this occur in my tank of cories, where a female (on her own due to last survivor) has spawned with a male of another species which happened to be one of two males of that species in the tank. But you do not want to encourage this, so maintaining decent-sized groups (including male and female in numbers) of each species should prevent hybridization, though nothing is ever cut and dried.

In case you're wondering what "lineage" is all about, it has to do with evolution of a species. A lineage is a group of species that all descended from the same ancestor species, and the clade is termed monophyletic. The genus Corydoras is polyphyletic, which means that the species now classified in this genus descended from more than one ancestor. Nine lineages within the present genus have been identified, and no one doubts this because every phylogenetic analysis to date has confirmed it. Eventually there will be nine genera in the family; one will be Corydoras, but the vast majority of the 465 known species will be in a different genus from the true Corydoras species. Aspidoras is within this classification (lineage 2), and Scleromystax (lineage 3), and the three former Brochis species are in subclade 1 of lineage 8.

Wow! That is very very cool, and wonderful to know. Thank you! So because pygmaeus are in the same lineage, they are capable if interbreeding, but not the habrosus? So if I wanted to have the mixed pygmy/dwarf cory tank, I should either 1. Have large, mixed gender groups or each species or 2. Choose between Hastatus and Pygmaeus to go with the habrosus?

I once kept hastatus and pygmaeus together

I currently have hastatus and pygmaeus in my 55 gallon community tank, but there is never a chance for babies because of the tetras.

 

[OliveFish05]

Some species of cory can interbreed, it depends on the lineage. Byron has told us that there are 9 different lineages and that cories in the same lineage canoften interbreed but those in different lineages are not likely to.
But I have no idea which lineage each of the three dwarf cory species are in. Byron and DoubleDutch may be able to tell you.

I've never heard of them interbreeding, (I once kept hastatus and pygmaeus together, with no hassle. The pygmaeus bred and the offspring all at least appeared to be pygmaeus). That said, they are clearly related and it's more than possible that hybridisation can occur, as it does with their larger cousins.
I don't believe that the nerites will eat the eggs, but there would always be a risk of that large, muscular, snail foot causing some damage, if it was to go atop a bunch.

Thank you for your help, I learned so much today!

 

[Byron]

So because pygmaeus are in the same lineage, they are capable if interbreeding, but not the habrosus? So if I wanted to have the mixed pygmy/dwarf cory tank, I should either 1. Have large, mixed gender groups or each species or 2. Choose between Hastatus and Pygmaeus to go with the habrosus?

Yes. So far as spawning/hybridization is concerned, this is generally true. However, again realize there is no guarantee--fish do not tend to read the scientific literature and they may sometimes act "outside the box" as it were!

I'll comment further on this below which may be of interest, but first let me say that I have kept C. pygmaeus and C. habrosus together (in groups of each species) but for some reason it just didn't seem to work. Nothing occurred between them, but they did keep their distances from each other (species wise) and I came to the conclusion that they would be best on their own and not combined.

Back to the lineages, there is an instructive parallel we can draw with the Marble Hatchetfish, Carnegiella strigata. This species has quite a large range over much of northern South America. Phylogenetic analysis has now determined there are two very distinct lineages within this "species," with a DNA variation in the 10-12% range which is considerable phylogenetically. For most of their habitats, they are primarily separated geographically. In other words, lineage 1 happens to dominate the Amazon basin from the city of Iquitos (Peru) to the city of Belem (Brazil) and includes the Caqueta River (Colombia), while lineage 2 is found in Guyana, Suriname and some regions of the Amazon channel.

Gery (1973) identified three types of this species, based upon variations in the pattern particularly the width of the mid-band across the keel. The first and second types have now been shown to correspond to the lineage 1 and 2 groups, while the third type is an intermediary form; according to Gery, the type 1 and 2 forms are sympatric between the city of Manacapuru and the Urubu River, and the third intermediary form is found in the Negro and Orinoco Rivers. The more recent phylogenetic analysis demonstrated that where these two types are sympatric (means they occur together) they do not interbreed, but only spawn within their respective lineage. This is the important factor...fish will basically spawn within their species/lineage and not outside it. The evolutionary factors of a lineage are very strong.

 

[OliveFish05]

Yes. So far as spawning/hybridization is concerned, this is generally true. However, again realize there is no guarantee--fish do not tend to read the scientific literature and they may sometimes act "outside the box" as it were!

Back to the lineages, there is an instructive parallel we can draw with the Marble Hatchetfish, Carnegiella strigata. This species has quite a large range over much of northern South America. Phylogenetic analysis has now determined there are two very distinct lineages within this "species," with a DNA variation in the 10-12% range which is considerable phylogenetically. For most of their habitats, they are primarily separated geographically. In other words, lineage 1 happens to dominate the Amazon basin from the city of Iquitos (Peru) to the city of Belem (Brazil) and includes the Caqueta River (Colombia), while lineage 2 is found in Guyana, Suriname and some regions of the Amazon channel.

Gery (1973) identified three types of this species, based upon variations in the pattern particularly the width of the mid-band across the keel. The first and second types have now been shown to correspond to the lineage 1 and 2 groups, while the third type is an intermediary form; according to Gery, the type 1 and 2 forms are sympatric between the city of Manacapuru and the Urubu River, and the third intermediary form is found in the Negro and Orinoco Rivers. The more recent phylogenetic analysis demonstrated that where these two types are sympatric (means they occur together) they do not interbreed, but only spawn within their respective lineage. This is the important factor...fish will basically spawn within their species/lineage and not outside it. The evolutionary factors of a lineage are very strong.

Wow. That is really interesting. Thank you for the info, I appreciate it very much and thoroughly enjoyed learning about the different lineages!

I'll comment further on this below which may be of interest, but first let me say that I have kept C. pygmaeus and C. habrosus together (in groups of each species) but for some reason it just didn't seem to work. Nothing occurred between them, but they did keep their distances from each other (species wise) and I came to the conclusion that they would be best on their own and not combined.

I have definitely noticed that when mine are out and about the tank (usually after a nice water change) that the hastatus stay with the hastatus and the pygmaeus stay with the pygmaeus. They don't seem to avoid eachother, though maybe if mine were in larger groups they would keep more to themselves.

I think I will choose two of the pygmy species, maybe even just stick with a school of hastatus, rather than trying to do all three. I will continue to research and plan, continue to try to locate some more of the hastatus. Thank you for your help!

 

[Byron]

Wow. That is really interesting. Thank you for the info, I appreciate it very much and thoroughly enjoyed learning about the different lineages!


I have definitely noticed that when mine are out and about the tank (usually after a nice water change) that the hastatus stay with the hastatus and the pygmaeus stay with the pygmaeus. They don't seem to avoid eachother, though maybe if mine were in larger groups they would keep more to themselves.

I think I will choose two of the pygmy species, maybe even just stick with a school of hastatus, rather than trying to do all three. I will continue to research and plan, continue to try to locate some more of the hastatus. Thank you for your help!

C. pygmaeus and C. hastatus are much more closely related (being in the same lineage), so one would expect more interaction than one would with either of these housed with C. habrosus.

I have a group of seven C. pygmaeus, all are surviving fry hatched out in my tank. I'm thinking of getting a group of this species to increase the shoal; my C. habrosus mix didn't really seem to work, and C. hastatus I have not seen locally for 15+ years. Here's a recent photo of the 7 pygmies, they frequently like to gather on the sponge filter, partly I suspect because of the plentiful infusoria on the sponges.

 

[OliveFish05]

C. pygmaeus and C. hastatus are much more closely related (being in the same lineage), so one would expect more interaction than one would with either of these housed with C. habrosus.

I have a group of seven C. pygmaeus, all are surviving fry hatched out in my tank. I'm thinking of getting a group of this species to increase the shoal; my C. habrosus mix didn't really seem to work, and C. hastatus I have not seen locally for 15+ years. Here's a recent photo of the 7 pygmies, they frequently like to gather on the sponge filter, partly I suspect because of the plentiful infusoria on the sponges.

I hadn't thought of that! Do you think that keeping the hastatus with either of the other kinds of pygmy cories decreases their quality of life? If it would be better to have one XL group (maybe 24) as opposed to 2 nice size groups (I was thinking starting with 8 to 12) I am totally open to that as well. My main goal is really just a cory focused tank!

Wow, they are gorgeous!

 

[Byron]

I hadn't thought of that! Do you think that keeping the hastatus with either of the other kinds of pygmy cories decreases their quality of life? If it would be better to have one XL group (maybe 24) as opposed to 2 nice size groups (I was thinking starting with 8 to 12) I am totally open to that as well. My main goal is really just a cory focused tank!

Wow, they are gorgeous!

They are cute, aren't they? They are three to four years old now, still very small, but I know they hatched out in the months prior to 2019.

I don't think there is any significant issues in keeping two species, but for some reason I just didn't think it was working when I had C. pygmaeus and C. habrosus together. The two closely-related C. pygmaeus and C. hastatus might be better so far as keeping two of the three together, and I would expect them to be intermingled a lot of the time. But we must remember that these species do occur individually in their respective habitats, never together; so far as I am aware, this is true for most (perhaps all) the Corydoras species, but regardless it certainly applies here. Given their friendly social nature it is not likely to be a serious problem.

 

[OliveFish05]

They are cute, aren't they? They are three to four years old now, still very small, but I know they hatched out in the months prior to 2019.

Aww. I absolutely adore cories, probably one of my favorite fish

Thank you for your help, advice, and input! I really appreciate it

 

[DoubleDutch]

May I add that hybridisation often seem to occure when females are outnumbered by males from the same species.

Even notorious crossbreeders as C.panda hardly crossbreed when enough female Pandas are available / when shoals are big enough.