cross breeds

hi all my small black calvus she is only around one and a half inch has breed with my large goldhead comp the eggs hatched around 3 days ago has this happened to anybody before and what will they look like when they get bigger there is 5 black calvus and 2 goldheads in the tank not sure what sex they are,,, thanks

Hi Noel,Ive never heard of them cross before,but i often read on US forums not to mix them.Hybrids are a big NO NO in our hobby,so if you want my advice let the fronts or other Altos pick them off;) .

P.s did Alans fish settle in alright?

Hi, I know this doesn't actually help answer noeleire's question, but I have a query about hybridisation. Dubfish mentions that hybridising fish is a 'big NO NO in our hobby' and I was just wondering what the rationale and reasoning behind it are? In nature, a natural selection process (assuming you believe in evolution!!!) will decide with whom an individual will mate. The fittest of the species are favoured (not eaten usually) and breed with the same 'fit' individual of opposite sex. In captive breeding, fish are bred purely for their looks, and importantly, not for their 'fitness', which by basic Mendelian Genetics will shrink the gene pool and possibly favour a negative gene. This can happen quite frequently in thoroughbred populations. The one I'm most familiar with is pure breed Alsatians (German Shepherds if you prefer)in Ireland that have quite a high percentage of intestinal problems, that can lead to sudden and excrutiatingly painful death, due to close breeding. Dogs that were more aesthetically pleasing were closely bred, which helped favour a negative mutant gene amongst the relatively small Irish Alsatian population.
If we move the same case to popular fish species can the same problems not arise? I have heard that most of our Guppys come from vast breeding tanks in Thailand where only the most colourful and choicest fish breed the next generation. Presumably under these artificial conditions most of the fish will be closely related (in fact, they have to be in many cases, due to the unnatural selection of mates), maybe even from the same birth/egg clutch. This will at least lead to a shrinking of the gene pool (and even potential speciation within the aquarium population, but that's another discussion). It is painfully obvious in our local aquariums when we see a captive bred and wild fish- the colour differences are dramatic in most cases. Now, I can understand allowing any fish with obvious flaws not to breed the next generation, but the perfectly healthy fish could be carrying the exact same mutated gene as his sibling. As the culling and breeding continue these flaws could get more pronounced in a population.
Now, to the point of my long ramble. Is it good for fish species to be so closely bred and encouraging each other to allow the hybrids to be eaten. Or, alternatively, would it not be better to allow the fish to breed and open up the gene pool again- let nature take it's course, as each of the fish found the other of reasonable fitness to procreate with. You never know, they might create beautiful fry. If nature didn't want the fry to be successful or the fish to mate, it will sort it out... well, naturally. This already happens in nature, either because mating will just not be successful, or the fry themselves won't be able to create successful offspring. (This latter is quite common. Anyone from a rural background knows that a male donkey and a female horse can mate to create a mule, but due to chromosomal numbers, the mule itself can't mate.)
So, not sure if I should have put this long post in here, but I'd appreciate any opinions on the matter.
(Perhaps a moderator could let me know if I should move this to a totally different topic.)

Interesting reading,but this is a Tropical/marine/coldwater FISH forum not a dog,horse,donkey or mule forum.Breeding hybrids to sell them or give them away, IMO will only destroy this hobby and the fishkeeping trade,here's a piece on hybridising fish.

www.aquaticcommunity.com/cichlid/hybrids.php

That article gives not one scientific reason why this person should not keep their hybrids

Hybrids occur naturally in nature and, if successful, survive and propagate a new species.

MANY fish diseases that occur in tanks can be linked back of over breeding, of small stock. Over Breeding of stocks will do more damage to fish species, in the long run.

If the OP has no intention of selling/giving away their hybrid, then there is no issue, even if they give them away and let people know what they are there is still not an issue. Especially if the new additions bring them pleasure.

at the very top of the article you say "in nature", aquariums are not by any means natural and you have a responsiblity to act accordingly.

ie. choosing tank mates that are suitable.

this could for the basis for an interesting discussion though(wow we're back on track)>I've never seen the atraction of hybrids myself,they never have the true beauty of either of the parent fish,just knowing that they will be infertile tells me that they just shouldn't be.

indeed the tank is not natural but the fish are, my "in nature" could, and should, read "naturally". If the off spring are healthy then there is also an onus on the owner to care for them

You mention the vibrant colours of the parents but these will have been selectively bred, to have such colours. Constant selective breeding causes trouble for all species (the earlier poster's comments about dogs are relevant)
Visual breeding can have unforseen dangers for a species. Captively overbred species may never survive in the wild, so this "consevation" argument is weak.

If people want hybrids, that are healthy, let them have them. If they want pure strains, let them have these.
As long as everyone is honest about the fish, that they have, there will not be a problem.

also the problem with most hybrids is that they are not healthy.Many fry are born deformed(parrots cant even close their mouth) bent spines or with health issues.

conversly over breeding or "pure" strains or inbreeding can case similar deformaties.

It is up to the keeper to be responsible and look after their fish.

i think its kinda un fair to say that noeleire is not responseable for his fish or that he doesnt look after them properly. im sure he never wanted them to cross breed and if any thing prob wanted each fish to mate with his or her s own strain. if any thing its just one of them random things and plus cross breeding has led to nice {all be it a anti christ of a fish} a flower horn. so if some one had a community tank witch many people do and 2 different species happen to breed that its not the owners fault.

it does happen that these fish will cross, and will continue to do so the only way to prevent this if thats what you want to do is to put max 1 of each species family in a tank, ie either altolamprologus compressiceps or altolamprologus calvus, psuedotropheus salousi or ps.crabbo, think you get my drift. if this is an accidental occurance which i think it is noeleire is not to be blamed, i myself hate / detest manmade hybrids and try to avoid them at all costs but if it happens as i think in this case through lack of knowledge re cross breeding then why hint at someone being an irresponsible fishkeeper, the fact he got fish to breed proves noeleire is keeping them right. now if this breeding was done deliberately i dont condone it. Noeleire if you do keep the fry thats your decision but if you do decide to pass them on i frrl you must let whom ever takes them know they are crosses so as not to pollute someone elses strain with hybrids
just my 2 cents

Hybrids????
Some of the general arguments (I mean in general, and not just those expressed on this forum) both for and against hybrids are very iffy.

The argument should not just be confined to ‘fish’ nor to any other specific taxa of animals……it is a global point of discussion.
IMO, using example from other taxa is fully justifiable in expressing opinions about hybridisation (but the analogies needs to be carefully considered before bold conclusions are made upon such analogies).

There are many questions that need to be answered, and actual science that need to be addressed, to enable a fuller take on the subject that doesn’t get too emotive.

I often hear words such as ‘heterosis’ (hybrid-vigour) being used in support of hybrids…..but that only applies if the hybrid actually shows heterosis; it is not a default of simply being a ‘hybrid’.
I often hear people utter …….“what is wrong with hybridising in captivity if it doesn’t affect the wild populations” …….to support willy-nilly breeding efforts; this can be rather disastrous when being concentrated into line-breeding.

Many species will form hybrids……some will even make viable intergeneric hybrids.

I don’t believe that having two ‘species’ cross breed in a tank is a sign of any irresponsible on behalf on the keeper.
It may, however, be a different matter to purposely do it for trade purposes….especially if done without careful study and a full investigation of the genetics.

Fish are a particular problem wrt what is a ‘hybrid’ and what is not.
There is lots of on-going work being done in classification and re-classification (especially of the cichlids). That body of work indicates some interesting currents that flow under the ‘species’….viz: “what is the species?”, “what is a sub-species?” or morphotype of the species?.

The fact that two species may cross-breed to produce viable offspring may even caste a question on whether or the classification of the original holotype was correct in the first place. That is a very interesting question…..and one that needs a bigger investigation in conservation efforts (ie exactly which species is attempted to be conserved or is endangered etc etc etc).

As for Mendelian Genetics…….I’m not concerned too much about the Mendelian Genetics as much as I am concerned over the Non-Mendelian Genetics in hybrids and line-breeding.

Simple traits are fine for Punnett Square educational purposes, but have little value in the real world of multi-gene animals.

All too often we see hybrids being produced on the basis of overt phenotypes (eg colour/shape/behaviour)…..yet seem to ignore the genotypes that may (or may not) express less obvious phenotypes (eg gut function, or detoxification systems)?

ian

The same thing can be said for selective breeding, of pure breeds though.

Pure breeds can be bred so far, for their highly desirable features, that their non advantageous features can be overdeveloped also

igmillichip wrote:

Fish are a particular problem wrt what is a ‘hybrid’ and what is not.
There is lots of on-going work being done in classification and re-classification (especially of the cichlids). That body of work indicates some interesting currents that flow under the ‘species’….viz: “what is the species?”, “what is a sub-species?” or morphotype of the species?.

This is very true. I think that there are a lot of "hybrids" out there that actually had parents of the same species (or were sub-species of the same species) which at the end of the day should be no worse than crossing a Collie and a German Shepherd or a German Shepherd and a Wolf.

I personally find "hybrids" between Guppies and Endlers to be quite aesthetically pleasing and I own quite a few of them. I am a zoologist by trade and I'm not all that familiar with fish classification (mammals and archosaurs are more my thing) but I feel that it's quite obvious that Guppies and Endlers are the same species or at least sub-species of the same species. They breed freely and there seems to be no fertility issues with the offsrping, either crossing with themselves or back to either parent strain.

Betta Splendens is another example. A lot of people are quite vocal about "hybridising" Bettas in the Splendens complex (Betta Imbellis, Betta Splendens, Betta Smaragdina, Betta Mahachai) when the fact is that the fish that we have in pet shops that is labeled as "Betta Splendens" are fish with genetic backgrounds that include at least three of those strains! Betta Spendens in the wild are not naturally metallic, Smaragdina and Mahachai are, our domestic Bettas only achieved their metallic varients by being crossed to Smaragdina and Mahachai.

However, if you are actually crossing different species and not strains of the same species then there can be problems with the offspring and that might not be the most responsible thing to be doing as a fish keeper.

Guppies (Poecilia reticulata) are closely related to Endler’s (Poecilia wingei). They do form viable and fertile hybrids; they also occur in the same natural waters: hence, there may even be a possibility that they produce hybrids in nature.

It may well become apparent that they are either the same or clearly distinct species….but that depends upon whether future zoologist will ‘lump’ or ‘split’, and the methodology used for classification purposes.

I’m not a zoologist, but I would have thought that general taxonomy and classification would have come into the realms of zoology though.

There is somewhat of difference between crossing a Collie and a German Shepherd, and crossing a German Shepherd and a Wolf. The former cross is effectively a cross of morphotypes or ‘breeds’; the later is an interspecific cross.

So, I suppose that there are different takes on the ‘level of hybrids’.

The plant world has lots of examples of very fine ‘hybrids’ though. Orchids, in particular, are one of the most obvious examples in our shops of both interspecific and intergeneric crosses. However, I would say that the level of polyploidy and chromosome non-disjunction allowable within the orchid family somewhat helps in the production of viable hybrids.

Siamese fighting fish are one example of fish where there has been a great history of researched line-breeding. My first book on Siamese Fighting Fish (by Dr Myron Gordon from the 1950s) was really a book on genetics. That book showed the legacy of careful work that had previously been put into Siamese fighter breeding. In fact, one of the publications that I recommend to fish keepers even today dates back to the 1930s.

But, where have those days gone?

The colours and iridescence of Siamese fighters depends upon not only expression of the genes, but upon how one phenotype may mask another because the effects of different layers of skin on the overall ‘colour’. So, I’m not totally convinced that the present or absence of metallic bits indicates inclusion of other species within the strains.

ian