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I just read through a thread where questions were asked about keeping some sort of hybrid fish (Blood Parrots) and it went up in flames. As a biologist who studied molecular genetics I know quite a bit about hybrids and mutants and from what I read in that thread there seems to be some confusion going on about how unnatural this is. I have the feeling that this is a dangerous topic to write about, so I do ask that everyone reads this calmly. If you disagree with what I write (this is my own personal view on this matter), feel free to comment and tell me on what, but keep your comments clear and to the point.

I'll start off with a controversial statement: Hybrids and mutants are two completely different kinds of beasts, both having perfectly natural positions even in the wild.

Now before you start replying, please read on what I mean with that.

A hybrid is simply the offspring of two different species that are genetically different, but still closely related enough to gestate. In general, hybrids are uncommon in the wild, because the different species tend to be geologically separated from one another, and simply will not meet under normal conditions. However, sometimes they do meet, with fish for example the flow of a river changes and contacts another waterway. If the species have similar shape and/or behavior, and have the genetic possibility to mate, then hybrids will form, even in the wild. Most of the time though, these hybrids have confusing behavior, strange coloring, or are sterile, and as a result will not mate, are unable to mate, or are simply killed off before they can mate. My point here is simply that hybrids DO occur in the wild and there is nothing "unnatural" about them except for what we as humans believe is "natural".

Mutations happen all the time and therefore mutants are much more common than hybrids. They are simply organisms where a tiny bit of DNA has changed and this can result in all sorts of changes, ranging from the shape of the fins, to the color of the eyes, etc. If you look at yourself, you will have plenty of cells that have undergone mutations (every single mole on your skin for example), does that make you unnatural? Some of those changes are heriditary - when they happen in the germ cells that produce either sperm or eggs - others aren't - like the moles on your skin. As mutants only have such a small change in DNA compared to the parental strains, their behavior isn't really changed and they generally will have no problem mating. This allows for selective breeding of those particular features that we humans find interesting or useful. The selective breeding is what has brought us the different kinds of dogs, cows, horses, goldfish, crops, etc. It is all based on small differences between individuals, i.e. mutations, which therefore are completely natural things.

A third kind of species I will bring up here is the transgenic fish (like the glowing zebrafish). These ARE unnatural fish, what happened there is that a gene from a jellyfish was taken and integrated into the DNA from the fish. Although DNA transfer between species DOES occur quite often in the wild (many viruses inject a cell with DNA for example), transgenic species are tailor made to have specific traits. The method by which this is done is still quite crude and imprecise and can have unforseen effects. The transgenic fish you find in stores are simply those that survived and did not show any clear averse affects to the transgene. Although I personally think that transgenic research is very important for better understanding of genetic diseases such as cancer, I also think that it is a dangerous technology that has the potential to do as much harm as it can do good. However, I don't want to turn this thread into a discussion about this topic.

A final subject to touch would be the dyed/tattooed fish. Dyeing a fish is purely cosmetic, it won't be heriditary, it won't affect the animal's behavior (unless it cripples the animal somehow) and it is purely done to make the fish more attactive for the customers. The fish will generally suffer quite a lot in the process, and in my personal opinion it should be banned.

Now to come back the "naturalness" of hybrids and mutants. Are hybrids and mutants unnatural? To some extent, yes. Some of the hybrids you find in the petshops result from species that simply would never meet in the wild. Others would possibly meet, but the resulting offspring wouldn't survive. The same counts for mutations, the beautiful long finned or highly colorful varieties of some species would simply not survive in the wild, where they would be easy prey for predators. Some hybrids are unnatural in the sense that they have been generated by artificially bringing eggs and sperm together, just to see whether the eggs fertilize and produce offspring. This makes the offspring about as unnatural as a mule (breed between horse and donkey) or a zorse (zebra and horse). One thing that should never be done with these "man-made" creatures, is releasing them into the wild without any research on how that would affect the natural habitat.

Whether you think this is a horrible thing or not, is completely up to you. Just to give you some food for thought, when you build up your aquarium at home, you're creating a completely unnatural environment for your fish. If you mix species and plants from across the world, you can't really speak about something being natural. Even a specific species tank where you try to make the tank as close as possible to the "natural" environment, you still have the unnatural situation of using different foods, having to make water changes, using different rocks/substrate, etc.

So, the real point of this wall of text is to make everyone think about what is really natural or not and whether your own personal opinion on it really changes anything. Just to give an example, I know that lots of people adore Chihuahuas, they find them cute and lovable. Personally, I can't stand the looks of them and find their goggle-eyed heads very "unnatural". Would a Chihuahua survive in the wild for more than a year? Unlikely. Should we release them into the wild? No, what would be the point?. However, they have a clear place in our society and as such I don't think they all should be destroyed because they are "unnatural". Just think about this next time when someone asks a question about a hybrid species.

ok i see where ur comeing from but when i set up a tank i try to mimic the natrual habitat by doing reaserch on the rivers, lakes, ponds, and location of the fish..... this hobby is unatrual the fish live in a glass box 90% of the time........ the thing is ur where talking about slective breeding and most of the time fish in the wild arnt gona breed slectively......... the main reason im not into hybreds is that one of the big parts of the HR669 was that the fish would get into the rivers and hybred or kill native fish.......... The other reason is that most of the pure bred fish are starting to slowly be taken over with hybreds.......... with the dyeing part and the cuting off of fins so they look cooler like a unicorn parrot is just messed up and to do it u cant be right in the head......... another problem is with the asian and florida breeders the pure breed strains of fish are starting to turn weak becuase of inbreeding by keeping hundreds in the same pond or breeding pool...... but thats just my opinion........

Havent read it all, too tired tonight, but i will say that blood parrots do not occur in the wild. How do i know? Theyre 99% infertile, have never been caught in the wild (many natural hybrid have), and are physically deformed in such a way that IMO fry would not survive in the wild...wait...wth am i doing?

hey mez, read it all first! there's nothing about blood parrots in the doctor's very interesting piece except for the opening line.

doc, thanks for putting the thought into it and giving some solid scientific background. mutation is the basis of everything, it's where we all come from, and without it the planet would not be as diverse as it is - and in our tanks mutation will consider to be attractive to some and not to others. but the long and short of it is that ALL our fish are mutants - it's just a matter of how long the mutation has been stable.

thanks again

the main reason i dont like hybreds is because they are takeing over the hobby its not really the dislikeing of the fish.......... some hybreds look great and some dont but the probelm about the hr669 ban in the USA is that enviormentalist see how easy it is to hybred fish and they are scared that they could comepletly destroy "pure" lines of fish even if they arnt 100% "pure" fish....... and from my experince most hybreds arnt steril i have found most cichlids and stingrays to be very fertil....... y was hokese post deleted??????

Yeah, i just guessed really as I think the first reffers to BP's, second to Flowehorns, and third is stated - that may just be the way i see it though.

I own a Synodontis catfish that I thought was a Synodontis decorus when I bought it, but after a closer look it turns out it was a hybrid. Although it's a perfectly stand-up fish, I'm a little disappointed that it wasn't a true S. decorus, which is a more attractive fish than the hybrid. This confusion could be prevented, of course, if there weren't hybrids being bred by breeders.

On top of this, proliferation of fertile hybrids increases the possibility of increased intermixing of these species in captivity, which not only makes it more confusing, but also means that the fish you think is a certain fish may not actually purely be that type of fish. Take the Endler's livebearer; some say that due to hybridization with the guppy, Endler's livebearers are increasingly actually hybrids with guppies and not pure Endler's livebearers. I'm sure this is the case with certain strains of platies and swordtails as well.

Except for the one hybrid Syno I have, I generally avoid hybrids, man-made strains, and especially dyed fish. Transgenic fish don't really interest me either. Yes, the aquarium is certainly an unnatural setting. My failure to care for most aquarium plants limits me to water sprite, a few crypts, and Anubias. My lack of exuberants amount of time and cash limit my other decor to a few stone pieces found in the backyard; my wood pieces include Mopani and Malaysian wood. The fishes in my aquarium come from different countries, and those that might share a country undoubtedly originate from separate rivers. I give my fish a regular food supply and electronically timed lighting, and their water comes out from a faucet rather than from the sky. These are not conditions that replicate nature in the least.

But, I can tell you what is natural. The fish. Well, except for the hybrid Syno I mentioned before. But the rest of the fish look, and for the most part act, naturally. I can respect the great diversity of fishes that have evolved over time in the comfort of my own home.

Of course, to each his own.

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The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.

Nice post Dr.B, also makes one think of the foods we eat, everything you buy in a grocery store is a modified version of the original food. Not only are they grown in greenhouses under heavy pesticide and herbicide application but they're picked long before they're ripe to be transported with minimal bruising and therefore the vitamins and nutrition is lost, but they're also hybridized and modified versions of the fruit or vegetable that was around 100, even 50 years ago.

^_^

Excellent post by Shinigami there. Good points by Babel regarding the food, although a lot of the stuff round here is produced (almost) naturally, especially the meat.
Now. I have another suggestion/theory.
We are seen as 'the top dog' on this planet, right? Now, whats natural and whats not natural? Arent we in the wild now? Are we hybrids? When we plant trees to harvest fruit from, is this natural because we are wild and we have thought this and executed it, or is it not natural because we planted it?

I'm glad to see this thread going well. I think it is pretty clear that most of the discussion is about what is natural and what is acceptable. Some people like to keep everything as natural as possible and consider anything that is not found in the wild as unacceptable. Others don't really care and just want to have what they think is pretty. The rest have opinions that lie somewhere in between.

The danger with topics that have no real regulation and which are open to such a wide array of opinions is that a few (very) vocal individuals with strong opinions can whip up a crowd into a witch hunt on those who have another (opposite) opinion. The problem may seem simple, you are asked to choose between "natural" and "unnatural", yet the couple of comments here in this thread already make it clear that it really is quite a complex issue that cannot be divided into these two statements.

Babel mentioned the food issue. Most (if not all) our current crops are the result of selecting and crossbreeding (hybridizing) of related species of plants. Farmers save seeds from plants that produce bigger leaves and plant those the next year, select the biggest producers from that crop and save the seeds from those plants to move on to the next year. This "inbreeding" of a species also brings up weaknesses, so they often also select a species that is stronger and cross that with their inbred species to make the line stronger. This is as old as humanity and without it, we would not have developed into such a widespread species as we are today. During my studies, one of the strongest examples of this selection has been the selective breeding of corn. Corn is one of the most important crop plants of today and was used by the native Americans for a very long time to make their bread. They did not really cultivate the plants and so we still have the native species of corn around and know what it looks like.

This is how much corn has changed over the last 500 years. From the small crop in the middle to the big cones on the right. That's not genetic engineering, but selective breeding, hybridizing, and fertilization.

Can we call this natural? I don't think you can easily answer that question. I personally "believe" in natural selection and evolution. I don't want to turn this into a religious discussion, so let's stay away from whether that "theory" is right or wrong, I'll just tell you what I think is happening and you are totally free to disagree with me on this if you think it's a load of ... nonsense

In my opinion, you can consider any environment as a situation where there is a certain amount of available resources (that are recyclable). Organisms (anything from bacteria to humans) simply make use of those resources as much as they can and try to prosper/propagate. For a corn plant under "natural" conditions, it simply is not cost effective to produce large amounts of seeds. It would cost the plant resources that simply are not available in the "natural" circumstances. Now, humans (and also some other animals) have the ability to alter their environment. We fertilize a piece of land, and as a result the plants that grow there now have these extra resources that make it possible to grow bigger. Humans aren't passive, we have a brain that allows us to "improve" the environment that we live in to make it more suitable for our own survival. It is in our nature to do so, which makes it in that sense perfectly natural.

That same brain also allows us the ability plan ahead and to question what we're doing. Some of the things can give us a temporary bonus now, but will have strong negative effects in the future, which makes it perhaps not the best thing to do. Making "designer fish" through hybridization is just one of many things for which we can't really see what sort of effect it has on our future. If we can keep them out of the natural habitats from which their parental species came, they should have no effect whatsoever, and it is merely an ethical issue of whether we have "the right" to do such things. If we set them loose in the wild and they push out the original species, driving them extinct, then this can potentially have huge effects on many other species. If this happens, then many people (including me) will consider this a very bad - unnatural - thing. The loss of a species due to human activity feels like an evil thing.

However, keep in mind that extinction also occurs naturally and that it is part of the cycle of life. With the disappearance of a species, resources that were used by that species now become free, eventually another species will come along and start making use of those resources. In a forest, when a big tree falls over and creates a big hole in the canopy, you suddenly have an explosion of new plants growing in the open area - plants that you won't really find elsewhere in the forest under the big growing trees. The same happens on a larger scale with species. The removal of one (or more) opens up opportunities for others, it just takes a whole lot longer (years, decades to centuries).

I know I'm not really giving any answers to what is right and wrong. That is simply because I don't think I have the answer. I believe dyeing fish is wrong, I think making transgenic fish just for cosmetic reasons is wrong (at least while we aren't sure that is has no negative effects on the fish). But in the end they are simply my own personal opinions and I don't have strong enough arguments and facts to back up these opinions to convince others to accept them.

I have no problems with the domestication of food plants. That is a matter of practicality, economy, and efficiency. My personal preferences for what pets to keep don't really have any bearing on my preferences for what I eat. Just because I like "natural" fish in my aquarium doesn't mean that I dislike agriculture.

I don't really have any qualms with selective breeding either, and while I keep it out of my tanks it's mostly because I don't have any interest in pursuing selective breeding. Transgenics as they have gone so far don't bother me, and at the current expense I don't see it picking up anytime soon anyway. Hybrids aren't entirely a problem for me either, unless it becomes a problem like it may be for the Endler's livebearers and other fishes where you have to question the "purity" of the fish you're getting. People just have to make sure to sell these fish as hybrids. I recognize that some people may believe forms of fish not found in the wild are more attractive and may want to keep them, and I'm not going to get in their way as long as the fish are healthy and happy.

Of course, when the health of the fish in its artificial form is questionable, I take issue. Painting fish is obviously disagreeable. Parrot cichlids are another issue since some of the selective breeding and hybridization efforts have resulted in some particularly grotesque fish that possibly hurt the fish. Personally, a no-tailed parrot cichlid is incredibly disgusting to me...

Despite how humans try to bubble themselves off from nature, we are still undoubtedly part of, and can greatly affect, the environment around us. The problem of extinction is a great one. I recognize that extinction is a completely natural phenomenon and has occurred for millions of years before we came here. On the other hand, the extinction rate is likely greatly increased due to human activity, and thus I for one believe that protection of the environment and biodiversity is extremely important to counteract this.

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The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.

With respect to hybrids, Dr Bonke is of course correct - natural hybrids DO exist (I've seen several documented among Centropyge angelfishes in the relevant scientific literature), and it's appropriate to consider the topic in a reasoned manner in the light of the evidence available to us that such natural hybrids exist.

However, one question that I certainly think we should be asking ourselves is this: should we be creating hybrids artifically simply for the sake of doing so? I would say no at this point, not least because I happen to think that the fishes we find in the wild are beautiful enough not to need any further tinkering from us - that tinkering is akin, in my view, to taking a rare orchid and deciding that what it needs is a day-glo spray paint job.

However, since some hybrids have been created, it's our responsibility as a species to care for them now that we\\\'ve brought them into the world. Personally, I would avoid buying them in the first place, and would prefer it if people were educated to realise that the vast array of fishes available to us from the natural world are more than enough to keep us supplied with beautiful spectacle and biological education for a dozen lifetimes each. Until that happens, we\\\'re going to see people trying to "improve" upon nature, without realising for a moment that this is, ultimately, a huge piece of conceit on the part of our species. I defy anyone to tell me that Mikrogeophagus ramirezi isn't spectacular enough in appearance in its own right to warrant interference of the sort we've seen taking place - you have a fish which, in its natural state, is adorned with scintillating bright yellow, black and red, and is covered with iridescent scales that, depending upon the angle at which you view them, vary from electric blue to violet. What more could you wish for? Moreover, the fish will live happily in our aquaria, breed in our aquaria, and in the process provide us with quite a bit of education about the responsibilities of rearing offspring, a lesson that sadly, some human beings in the news continue to demonstrate a need for. Personally, I consider that the wild type fish is enough of a catwalk star on its own merits not to need our interference in this vein.

Moreover, the conceit that leads to trying to "improve" upon nature has led to some practices that are in my view, and presumably the view of many here, ethically abhorrent, such as the dyeing of various fishes, which involves subjecting those fishes to a level of misery and suffering that is wholly at variance with proper notions of care and husbandry. The sooner those practices are brought to an end, the better in my view.

If something odd appears among the fry during our breeding programmes, this is different, especially if that oddity happens to be perfectly capable of surviving and reproducing as well as its "normal" siblings. Such occurrences provide valuable biological lessons, and it's only natural for us to ask the question "is it possible to produce more like it?" Some of the best-loved aquarium fishes started out this way, and I've no complaint to raise against those - for example, elsewhere I've been using the double tail mutation in Betta splendens as an evolutionary education tool, not least because it happens to possess nice, simple Mendelian inheritance patterns making it easy to use for the purpose. On the other hand, deliberately producing teratomatous monsters is something I have no wish to pursue, or for that matter to see pursued, with the exception of valid medical or veterinary research that will ultimately yield benefits for us and for our fishes further down the line. I find the mindset that isn't satisfied until it's pushed the production of bizarre, outlandish forms to the limit in pursuit of a wholly dubious aesthetic, equally as disturbing as the mindset that brought us foot binding for women. I home I'm not in a minority with respect to this.

Panda Catfish fan and keeper/breeder since Christmas 2002

Wow, I never knew it was such a hot topic! Very interesting. Also didn't know Blood Parrots weren't "natural", if you will.

I guess I have a lax opinion on it. If it's not hurting the fish/environment/etc. I don't have much of a problem with it. As it is, I definitely don't agree with tattooing a fish. Ugh, it makes me think of the lady who was selling 'goth kittens' on Ebay, they were pierced and stuff. Ew. Just totally unnecessary.

EDIT: I just read up a bit on the Blood Parrots. Whoa. In that particular case, I would say I don't find that ethical and wouldn't support any hybrids that create a body 'deformity' that could cause death, pain, suffering, or whatever to a fish, just for the sake of it's looks. Boo, whoever created them!