Need your opinions on my cory situation

[Byron]

@Byron
Okay I understand THAT you are against it. My question is WHY. I don't really see a big deal and just want to understand a bit better. Many people stand firmly against things - such as ANTI VAXXERS. It doesn't necessarily mean that their stance makes any real sense or has any real purpose. I'm not saying this is such a case, I'm just trying to understand why it's such a major deal to certain groups.

No, it is most certainly nothing even remotely similar. This is not the place for that issue, let's stick to fish.

The "why" was very clearly stated in my previous post. This is a "no" among the scientific community who understand biology. And Ian's point is very well taken.

 

[Guest14017]

I happen to be one that LIKES the GMO fish. Fancy goldfish, fancy guppies, Blood Parrots etc. I see my loves being bashed left and right. Fancy goldfish owners in particular are the laughingstock of the hobby. With proper care, they actually do okay oftentimes. They're just hard to care for due to their special needs.

But when you search swim bladder problems in fish, you'll generally see a ridiculous upside down Fancy goldfish that people are calling names etc. When you search dropsy, you'll see a pineconed goldfish first usually.

Despite the fact that many of these small tropicals don't live any longer than goldfish and have tons of issues with them all dying left and right in people's tanks - it's the goldfish that take the beat down.

So I am USED to my fish being talked down on - doesn't stop me from liking them. I just wanted to gain an understanding.

After all, an invasive species is an invasive species. The fish doesn't need to be a hybrid to be invasive. Not at all. The reasons stated didn't really make enough sense to me to be a big deal - but maybe I am just missing something. As for the hypothetical I used, it wasn't to discuss that... it was to make a point that just because a group of people stand against something (such as your example of animal rights groups) doesn't necessarily mean it's right or sensible.

As for ANIMAL RIGHTS GROUPS - they wish to end keeping pets PERIOD. Not just fish. They believe keeping pets at all is wrong and we use them and cage them up for our entertainment. Over here where I live, they are a joke and will never be taken seriously or given any type of power... so the issue of hybrid fish in this hobby I think bears no real relevance to them.

 

[Byron]

While I agree with @Byron on this issue, to play devil's advocate, no-one seems to see the harm in doing the same thing various kinds of Cichlids and Livebearers. Though I suspect that will be the point that @Byron will make, do wild guppies still exist for instance, or do we just have global feral populations of escaped mutts creating havoc in local ecosystems?

The issue is relevant to all natural species. I exempted livebearers previously, or to be more correct, I said the development of varieties/colours among them and other fish was not hybridization but selective breeding. When cory species "x" is near to extinction because it only occures in one location (and this applies to many of them) our efforts--if we care about our world--should be to rectify that. The end result may be maintaining that species in aquaria, or future generations will never see it. It literally brings me to tears when I consider the many species on this planet that will become extinct before we have even discovered them.

As for released artificial strains damaging the ecosystem...we've done this more than once.

 

[Byron]

I happen to be one that LIKES the GMO fish. Fancy goldfish, fancy guppies, Blood Parrots etc. I see my loves being bashed left and right. Fancy goldfish owners in particular are the laughingstock of the hobby. With proper care, they actually do okay oftentimes. They're just hard to care for due to their special needs.

But when you search swim bladder problems in fish, you'll generally see a ridiculous upside down Fancy goldfish that people are calling names etc. When you search dropsy, you'll see a pineconed goldfish first usually.

Despite the fact that many of these small tropicals don't live any longer than goldfish and have tons of issues with them all dying left and right in people's tanks - it's the goldfish that take the beat down.

So I am USED to my fish being talked down on - doesn't stop me from liking them. I just wanted to gain an understanding.

After all, an invasive species is an invasive species. The fish doesn't need to be a hybrid to be invasive. Not at all. The reasons stated didn't really make enough sense to me to be a big deal - but maybe I am just missing something. As for the hypothetical I used, it wasn't to discuss that... it was to make a point that just because a group of people stand against something (such as your example of animal rights groups) doesn't necessarily mean it's right or sensible.

As for ANIMAL RIGHTS GROUPS - they wish to end keeping pets PERIOD. Not just fish. They believe keeping pets at all is wrong and we use them and cage them up for our entertainment. Over here where I live, they are a joke and will never be taken seriously or given any type of power... so the issue of hybrid fish in this hobby I think bears no real relevance to them.

Well, I can't even logically respond to this as there is clearly no base from which we diverge. You do not have an understanding of science on which logic can be built. As someone who understand biology, I see the danger. It has nothing to do with invasive spcies. And it has nothing to do with your likes; to say that one's liking "x" is justification for agreeing/allowing/doing it, recognizing the cost, is something I can't even fathom.

And I really am sorry if you live somewhere where the cruelty to animals and their extinction is a joke. I did not say the animal rights activists were right (or wrong), but they are being fueled by a number of reckless and non-caring practices like the one we are discussing.

 

[Guest14017]

Well, I can't even logically respond to this as there is clearly no base from which we diverge. You do not have an understanding of science on which logic can be built. As someone who understand biology, I see the danger. It has nothing to do with invasive spcies. And it has nothing to do with your likes; to say that one's liking "x" is justification for agreeing/allowing/doing it, recognizing the cost, is something I can't even fathom.

And I really am sorry if you live somewhere where the cruelty to animals and their extinction is a joke. I did not say the animal rights activists were right (or wrong), but they are being fueled by a number of reckless and non-caring practices like the one we are discussing.

Nope I do not have an understanding of the science you speak of or use to defend your statements. I said that multiple times. And you cannot really seem to explain it so nevermind. Thanks for replying. Have a nice day.

 

[anewbie]

We need to be clear as to what hybrid and hybridization mean. We are not talking about varieties of livebearers, or selective breeding to obtain varieties as with the gourami Trichopodus trichopterus. But we are talking about distinct species being forced into hybridization to create a new distinct species.

The scientific community does not support nor agree with such hybridization. No responsible aquarist in this hobby should encourage hybridization or be complacent about it. As a race we have done more than enough to destroy this planet, there is no point in furthering this destruction.

The "animal rights" people would like to end this hobby completely, and people being irresponsible only gives them fuel for their fire.

Corydoras species were the primary issue here, so Ian Fuller's explanation covers it; Ian established and owns CorydorasWorld which is the prime source of reliable information on the Corydoradinae. He has spent over 50 years investigating and collecting species of Corydoras, and there are very few with more knowledge on the subject.

In nature some species do occasionally cross, especially at a time when severe conditions bring species together that would not normally be found in the same place. This is known in science as speciating. In the Hobby the species would have to be purposely put together and that would create unnatural crosses, and then we would end up with these hybrids expanding into the hobby and ultimately spoiling the two crossed species.​

​

This page was originally set up to compliment the Corydorasworld.com website, and promote the keeping, breeding and well being of Corydoradinae Catfishes, with a view to maintaining and establishing species that maybe/are endangered in the wild. There are probably in excess of 300 naturally occurring Corydoradinae species, many of which are in danger of becoming extinct in their natural homes and I would like to see efforts being made to preserve these species. I realize that it will be an almost impossible task to try and reinstate aquarium bred specimens back into their natural homes, mainly because these are being or have been destroyed. It is possible however to maintain these species in aquaria and that is what I would like to see. To this end a new data base of registered keepers/breeders has been established on the web site.​

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A post has been made showing and promoting hybridization of Corydoradinae species. This is something that I am 100% against and therefore I will in future delete any such posts that promote this activity.​

One comment i have in this is that I would presume that a lot of these fishes occur together in the wild; what prevent hybrid forming in nature? My presumption has been that they do occur in nature but frequently they are not viable and quickly die out. However where viable i would presume that some of these 'species' that are discovered were at one time hybrid that had occurred in nature. Is this not the case ?

 

[Myraan]

The fact that they are recognized as separate species and given the choice will only breed with their own kind is partly what defines as species. The fact that they breed makes them biologically the same species, but they have been geographically separated which allowed the two populations to evolve separately and speciate; by definition they rarely if ever meet in the wild.

In the UK Common Gulls and Herring Gulls are separate species that I believe do not hybridise. They are the result of the ancestral bird gradually expanding its territory east (or west, I forget), and gradually changing slightly from the parent population, but still able to interbreed with neighbouring populations. By the time they have expanded west (or east) all around the world they are a separate species to the one that was already there. Scientists discovered this from molecular analysis of populations all around the northern hemisphere. Their DNA sequences vary in such a way that it's difficult to determine which of the two the population on the other side of the world is; only in western europe are two species recognized.

My understanding of the Corydoras issue is that very little is known in detail about this large clade. What we describe as C.aenus is actually a large group of closely related species that all look almost the same; the "type" specimen is native to the island of Trinidad and such may very likely be more distantly related to the ones found all over South America than we realise. Ones we see in the hobby by now are already a horrible mix of hybrids I suspect, and as a result any reporting of their ideal parameters would be a guess. It's fortunate that we have found out that they are quite hardy in a range of temperatures. Scientists are likely against hybridisation because they still haven't sorted out who is related to who and exactly what rivers they originate from. They cannot trust samples taken from the hobby, they must only be able to use samples they collect themselves or from collecters who know where there breeding line was sourced.

The big problem with that is because of human behaviour habitats in the Amazon are being lost and it is likely extinctions in the wild we do not know about have already happened.

 

[Guest14017]

@Myraan
This makes sense from a scientific standpoint. I'm unsure of why it seemed impossible to explain when I asked someone else.

 

[itiwhetu]

Cross breeding very rarely occurs. A lot of factors all must line up for it to happen. I would be putting all the fish together and let them have a happy life. We have someone thinking they have a cross between a Molly and a Guppy. Sometimes we get carried away with all the possibilities and stop enjoying, just keeping fish.

 

[Byron]

One comment i have in this is that I would presume that a lot of these fishes occur together in the wild; what prevent hybrid forming in nature? My presumption has been that they do occur in nature but frequently they are not viable and quickly die out. However where viable i would presume that some of these 'species' that are discovered were at one time hybrid that had occurred in nature. Is this not the case ?

Generally, no. With a very few exceptions, a species of cory in any given area is the only species living there. River systems are huge in South America; the Amazon River basin is the size of the continental USA (minus Texas I believe), and the Rio Negro basin is the size of France in area. Within these basins many of the cory species are endemic to a specific creek or stream, or if they are found in larger rivers they are likely the only species in that specific area. A species that becomes divided geographically may remain as the same species in both areas, even though geographically isolated; or one or both of them may evolve into a new species. But there is, so far as I know, no evidence of hybridization. Species have a strong desire to only mate within their species. In nature this is relatively easy. It is when the aquarist puts two species together in an aquarium, and then as I have previously said does not provide a sufficient group of each, that cross-species spawning is likely to occur. But in their habitats, no.

In the 1990's the British ichthyologist David Sands collected several cory species in norther tributaries of the Rio Nego, and he discovered and subsequently described to science several new species. C. duplicareus was one of these, and this species is endemic to the Rio Poranga, a stream that joins a small tributary of the upper Rio Negro, Brazil. Dr. Sands in his article on the collecting noted that species remain within their respective creek, even though they could, if they so desired, easily swim around to the next creek; but they do not appear to do so.

This all applies to other fish than cories. The Marble Hatchetfish is one case in point. More recent phylogenetic analysis has shown that while the genus Carnegiella is monophyletic, the species C. strigata is not. Examination of populations within the Negro and Uatuma blackwater rivers has revealed two monophyletic lineages within this species, with considerable genetic distance (10-12%) between them, making it probable that there are two distinct species within this complex (Schneider, et al, 2012; Abe, et al, 2013). The differentiation of C. strigata into distinct forms, the strigata type (S type), fasciata type (F type) and intermediate type (SF), was previously described by Gery (1973) [in the days before we had phylogenetic analysis available] based on differing band patterns in external morphology. The geographical distribution of the S type is Guyana, Suriname and some regions of the Amazon channel; the mid-band is thin and divides into a “Y” midway. The distribution of the F type is reported to dominate the Amazon basin from the city of Iquitos (Peru) to the city of Belem (Brazil) and includes the Caqueta River (Colombia); the mid-band is solid and wider by contrast to the S type pattern. According to Gery (1973), the two forms are sympatric between the city of Manacapuru and the Urubu River. Phylogenetic analysis has shown that the two distinct forms of this species, in areas where they do co-exist, never cross-breed. The two lineages remain distinct. It is nature's way.

 

[OliveFish05]

Ok, so I looked into the marbled hatchets and green neons, but don’t have any way to get them in my area. Aside from having them shipped in, of course. My LFS has silver hatchets, but I don’t care for the look of them as much.

My GH is 5. I’ve got 1 BN Pleco, 13 Pygmy cories, and plan to add some nerite snails and cherry shrimp. I can’t get marbles hatchets or green neons. I’m trying to take into consideration the important factors for choosing my “centerpiece”.

It has to be peaceful
It has to do well in both my water parameters and tank setup (soft water, heavily planted, low flow, lots of bottom dwellers)
It has to be small, so as to fit in my tank (20 long)

Would a group of 4 honey gourami work? If not, I think I will leave the tank how it is, with the pleco, cories and a plan to add shrimp and snails and continue to watch out for some marbled hatchets.


I know we talked about honey gourami with Pygmy Cories in the past. The biggest thing I remember being important was the fact that the honey gourami needed low flow and lots of floating plants.

 

[Byron]

Ok, so I looked into the marbled hatchets and green neons, but don’t have any way to get them in my area. Aside from having them shipped in, of course. My LFS has silver hatchets, but I don’t care for the look of them as much.

My GH is 5. I’ve got 1 BN Pleco, 13 Pygmy cories, and plan to add some nerite snails and cherry shrimp. I can’t get marbles hatchets or green neons. I’m trying to take into consideration the important factors for choosing my “centerpiece”.

It has to be peaceful
It has to do well in both my water parameters and tank setup (soft water, heavily planted, low flow, lots of bottom dwellers)
It has to be small, so as to fit in my tank (20 long)

Would a group of 4 honey gourami work? If not, I think I will leave the tank how it is, with the pleco, cories and a plan to add shrimp and snails and continue to watch out for some marbled hatchets.


I know we talked about honey gourami with Pygmy Cories in the past. The biggest thing I remember being important was the fact that the honey gourami needed low flow and lots of floating plants.

I don't see a real issue with the honey gourami and cories, even pygmies. Some other gourami would likely not work though. I think I've said elsewhere that I do not like "centrepiece" fish in small tanks, but that is just me. I think any tank under 30-40 gallons should have consistently similar-sized species, they are in my view anyway much more effective and less likely to be problematical.

"Silver Hatchets" usually refers to one of the larger hatchetfishes, the species in the genus Gasteropelecus and Thoracocharax. These are larger and more active in general, and personally I would want a 3-foot minimum tank for any group of these species. Peaceful but a bit "much" here. There are two plainer species in Carnegiella, C. marthae and C. myersi, that are like the Marbles in everything but patterning. C. myersi is very delicate, the smallest known hatchetfish, and not always easy, but C. marthae is rather a nice little fish. For some reason the Carnegiella species are very rare; I was astounded to see them recently in a Mr. Pets of all places.

Paracheirodon simulans (green or false neon) is more readily available these days, due to being bred in outdoor ponds in SE Asia. Almost "wild" in that sense.

 

[OliveFish05]

I don't see a real issue with the honey gourami and cories, even pygmies. Some other gourami would likely not work though. I think I've said elsewhere that I do not like "centrepiece" fish in small tanks, but that is just me. I think any tank under 30-40 gallons should have consistently similar-sized species, they are in my view anyway much more effective and less likely to be problematical.

Ok. I was considering a single male dwarf gourami, but through looking into it more it seems they are more known for aggression, as well as the irridovirus (I hope I spelled and worded that right). I know the Pygmy Cories are just under an inch, the Pleco about 2 and a half inches, and as far as I can tell honey gouramis get about 2 inches. Is this size difference a likely issue? I may have used the wrong word when I said centerpiece. When I think of a centerpiece fish, I think of something that stands out either in color, numbers, or behavior rather than size. For example, a mystery snail in a tank of shrimp. A BN pleco in a tank of Cories. Of course size does contribute to the feeling of it “standing out”, and I suppose this is what most people refer to when they think of “centerpiece”?

"Silver Hatchets" usually refers to one of the larger hatchetfishes, the species in the genus Gasteropelecus and Thoracocharax. These are larger and more active in general, and personally I would want a 3-foot minimum tank for any group of these species. Peaceful but a bit "much" here. There are two plainer species in Carnegiella, C. marthae and C. myersi, that are like the Marbles in everything but patterning. C. myersi is very delicate, the smallest known hatchetfish, and not always easy, but C. marthae is rather a nice little fish. For some reason the Carnegiella species are very rare; I was astounded to see them recently in a Mr. Pets of all places.

Ohhhhhhhh ok. I don’t recall which the LFS had. That is very interesting! I think all the hatchetfish varieties are just so incredibly unique. The way they jump makes me very nervous though. I was able to look a few months back on my LFS “freshwater spotlight, this is what we got in this week” thing and they have had the marbled hatchet fish, but who knows when or if they will have them again. It seems like it was a bit of a special thing.

Paracheirodon simulans (green or false neon) is more readily available these days, due to being bred in outdoor ponds in SE Asia. Almost "wild" in that sense.

Ohhh ok. I was able to find some online for $2 a piece, which isn’t bad, but the shipping alone was $60-$80, unless I spend $400 which is not happening any time soon (Or likely ever).

I appreciate your help and advice very much. It absolutely amazes me how knowledgeable, patient, and helpful you are!

 

[Byron]

Ok. I was considering a single male dwarf gourami, but through looking into it more it seems they are more known for aggression, as well as the irridovirus (I hope I spelled and worded that right). I know the Pygmy Cories are just under an inch, the Pleco about 2 and a half inches, and as far as I can tell honey gouramis get about 2 inches. Is this size difference a likely issue? I may have used the wrong word when I said centerpiece. When I think of a centerpiece fish, I think of something that stands out either in color, numbers, or behavior rather than size. For example, a mystery snail in a tank of shrimp. A BN pleco in a tank of Cories. Of course size does contribute to the feeling of it “standing out”, and I suppose this is what most people refer to when they think of “centerpiece”?

Ohhhhhhhh ok. I don’t recall which the LFS had. That is very interesting! I think all the hatchetfish varieties are just so incredibly unique. The way they jump makes me very nervous though. I was able to look a few months back on my LFS “freshwater spotlight, this is what we got in this week” thing and they have had the marbled hatchet fish, but who knows when or if they will have them again. It seems like it was a bit of a special thing.


Ohhh ok. I was able to find some online for $2 a piece, which isn’t bad, but the shipping alone was $60-$80, unless I spend $400 which is not happening any time soon (Or likely ever).

I appreciate your help and advice very much. It absolutely amazes me how knowledgeable, patient, and helpful you are!

Thank you indeed, you are very kind. I do try to help.

Large fish (comparatively speaking) in smaller tanks tend to make the space look even smaller. A group of honey or dwarf gourami (thinking size only here) in a 3-foot tank is one thing, but in a 2-foot not so good, just from the visual. My 29g blackwater tank has 43 fish, and still room for a couple dozen more (when I see what I want, no hurry). It has become my favourite tank, simply because of the variety possible.

 

[OliveFish05]

Large fish (comparatively speaking) in smaller tanks tend to make the space look even smaller. A group of honey or dwarf gourami (thinking size only here) in a 3-foot tank is one thing, but in a 2-foot not so good, just from the visual. My 29g blackwater tank has 43 fish, and still room for a couple dozen more (when I see what I want, no hurry). It has become my favourite tank, simply because of the variety possible.

That makes sense. Makes me think of a group of full grown discus in a 75 gallon tank. While the tank size is technically ok and it looks very nice, it looks a little “off”.

I called my LFS and they said they occasionally get the marbled hatchetfish. It looks like they had some a couple months ago. I will skip the gouramis and wait for the marbled hatchetfish so the sizing in the tank doesn’t look off.

Does this stocking sound ok

Gh - 5
Ph - 7
Tank size - 20 long (30x12x12)
tight fitting lid
lots of plants, both floating and planted

13 Cories (pygmae and hastatus)
1 bristlenose pleco
2-5 nerite snails
a group of red cherry shrimp
8-12 marbled hatchetfish

it is probably silly of me but I have names for all the fish and snails in mind already if that looks good, I promise I’ve made up my mind! The only thing now that I wasn‘t sure about was how soft the water is for the shrimp and snails