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Danio margaritatus-erythromicron hybrids?

Home Forums Fresh and Brackish Water Fishes Danio margaritatus-erythromicron hybrids?

This topic contains 0 replies, has 1 voice, and was last updated by  Matt 6 years, 3 months ago.

Viewing 15 posts - 16 through 30 (of 31 total)
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  • #351556

    coelacanth
    Participant

    @matt said:

    @Rüdiger said:

    P.S. I sincerely apologize for the typo in “breading”.Embarassed

    Haha no worries, think we all like ‘hot bread’. Laugh Thanks a lot for the pics will add them now.

    As a result of this thread Johnny has made a new page for the fish on his website.

    @coelacanth are some of the original fish still alive?

     

     

    I like warm baps and soft muffins myself.

    We don’t know TBH, we very rarely have a loss in that tank, it’s densely planted so there always the chance of an ex-fish being missed.

    #351559

    BillT
    Participant

    I do suspect that it might be promoted by years of “hot breeding”.

     

    What exactly is hot “breeding”? I am not familiar with that term.

     

    In addition to bad genetics, body axis malformations can result from microsporidian infections. Symptoms like this are well known in zebrafish labs. Neon tetra disease is an example of a microsporidian disease. The infectious agent is small cells that live inside of the cells of the host except when as spores it can infect other cells. In zebrafish, these infections can result in the destruction of muscle and skeletal tissue leading to shapes like this arising later in life. A late in life appearance would indicate to me a disease rather than a genetic problem.

    Alternatively, malformation problems like this can also arise for nutritional problems (not that I am expecting that people reading this would have poorly nourished fish). These would be expected to show up early in life rather than later and would be more difficult to distinguish from an early onset genetic problem.

    #351560

    mikev
    Participant

    In addition to bad genetics, body axis malformations can result from microsporidian infections.

    Do you have any additional information on this, or hopefully some papers?

    (I believe I have encountered this a few times, specifically in zebrafish but not other danios, initially attributed this to tb, but it does not seem the case)

    #351561

    BallAquatics
    Participant

    Matt said 

    How common are these fish in the trade Dennis?

    Matt, I don’t import fish for resale, but over the years I have purchased groups of these fish from 7 different sources to make up my breeding groups.  I have never seen one of these fish in the flesh, and only in the two photos that have been referenced.

    I do have some very nice D. margaritatus and also D. erythromicron so perhaps this fall I’ll have to set them up and see what the out come is…..

    Dennis

    #351565

    BillT
    Participant

    Do you have any additional information on this, or hopefully some papers?

    There is a lot published on zebrafish infections, mostly because of reserch labs wondering what’s wrong with their lab fish.

    I am inferring the possibility of the same infection in these other Danios by the same disease organism with the same symptoms. Other than for zebrafish, there is almost no research on Danio fish diseases. The zebrafish disease researchers are however interested in finding their favorite diseases in related species and have done that on occasion.

    A good general reference would be the zebrafish stock center’s disease manual: “Diseases of Zebrafish in Research Facilities” which has several references in it.

    The disease manual can be obtained at:

    http://zebrafish.org/zirc/health/diseaseManual.php

    Microsporidiosis is in the protozoan section of the manual.

     

    There is also information on mycobacteria in the manual. I think this most often becomes obvious when the fish get open sores or reddish areas. However, these symptoms alone do not a good diagnosis make.

    #351566

    mikev
    Participant

    Thanks, Bill,

    No, I’m fairly sure it is not TB — never open sores, for instance, and good evidence that the cause is protozoan. Definitely infectious. Let me read the reference carefully, but it does not seem to be this: I’m not seeing much of emaciation.

    A late in life appearance would indicate to me a disease rather than a genetic problem.

    Actually, there is another possibility. I’ve seen this more often with blue eyes but also with danios, not infectious, not treatable, and usually not life threatening, most likely some metabolism breakdown in older fish and resulting calcium loss.

    #351567

    Matt
    Keymaster

    If the physical deformities can potentially be attributed to disease, what about the aberrant colour pattern in the fins?

    Perhaps a combination of factors are at play?

    #351568

    coelacanth
    Participant

    @mikev said:
    Actually, there is another possibility. I’ve seen this more often with blue eyes but also with danios, not infectious, not treatable, and usually not life threatening, most likely some metabolism breakdown in older fish and resulting calcium loss.

    I’d go with this as a potential cause on many occasions, particularly given that we keep fish well beyond what I’d expect their natural lifespan to be.

    #351572

    torso
    Participant

    @BillT said:
    I do suspect that it might be promoted by years of “hot breeding”.
     What exactly is hot “breeding”? I am not familiar with that term.

     

     

    #351573

    torso
    Participant

     

    Hi Bill

    Did I miss the explanation?

    “Dampfzucht” of “Hot breeding” started in the late seventies. Hobby-breeders tried to make a business with the breeding of sweetwater-fish. For this the fry had to be brought up in the shortest time possible. Quantity and fast growth was the aim. For this the fry was held at the highest temperature possible, food was given in form of pellets from the commercial breeding or other “nutritous” food (beef haert e.g.), stocking them in very small tanks, daily water change/strong filtering, antibiotics at the minor health problem

    Degerenated looking specimen were sorted out, but the internal defects led to short life, high vulnerability for deseases etc

    I only once had the chance to see a breeder at work, Corys etc. It was shocking.

    Cheers Charles

    #351574

    mikev
    Participant

    Blue eyes cases tend to show up at 1.5-2 years age. Typical lifespan in the wild is about 1 year, and for most 2 years in good conditions in captivity. I lost one p.pellucidus like this last week.. the fish was 2.5+ year old and symptoms were visible for nearly a year… so yes, beyond the natural lifespan. Not every aging blue eye develops this, however, perhaps 10-20%.

    As for margaritatus/erythromicron… it is so common that my feeling that this is “normal” age-related change?

    #351576

    BillT
    Participant

    If the physical deformities can potentially be attributed to disease, what about the aberrant colour pattern in the fins?

    Perhaps a combination of factors are at play?

     

    Neon tetra disease is also a microsporidian disease. It also affects color. I think the effects of these organisms is to some extent determined by the tissues in which they reside in the fish’s body.

    #351577

    BillT
    Participant

    “Dampfzucht” of “Hot breeding” started in the late seventies. Hobby-breeders tried to make a business with the breeding of sweetwater-fish. For this the fry had to be brought up in the shortest time possible. Quantity and fast growth was the aim. For this the fry was held at the highest temperature possible, food was given in form of pellets from the commercial breeding or other “nutritous” food (beef haert e.g.), stocking them in very small tanks, daily water change/strong filtering, antibiotics at the minor health problem

    Degerenated looking specimen were sorted out, but the internal defects led to short life, high vulnerability for deseases etc

    I only once had the chance to see a breeder at work, Corys etc. It was shocking.

    Thanks for the explanation Charles.

    Except for the use of antibiotics, the treatment you described sounds like big zebrafish research facilities. I was involved with this for several years. Differences include not a profit motive but certainly a motive to save money to use on other things. Antibiotics almost never get used (where I was). Strict and very effective quarantine procedures and Klingon health care techniques (killing the victim to prevent spread) were used instead. The motive to go fast is based on going through more crosses in a given time (doing more genetics) and doing more experiments. In labs, this can usually be done well but it takes a lot of money and effort.

    In addition, it has been possible to get problems diagnosed by fish vet researchers so that causes of problems could really be understood and addressed. I’m guessing this is very uncommon among fish keep as pets. Mostly, this intense level of treatment is restricted to food fish (aquaculture), very expensive fish (Koi), research animals (especially zebrafish which are in something like 900-1000 labs worldwide), and maybe specific conservation cases.

     

    The defects you listed might also be attributed to poorly done inbreeding.

    I have seen this several times in lab wild type (WT) lines (used as non-mutant lines in crosses). On the other hand some of these lines have been bred for probably 90-100 generations (although usually with ~200 parents per generation) and some of them look pretty good and are pretty robust (although usually a bit smaller than farm raised ZF, not so sure about the fish from the wild).

    It would surprise me if poor inbreeding are often combined with other forms of poor care.

     

    My Inbreeding Explanation:

    Zebrafish (taken as a representative fish) have about 30,000 genes (counted as transcription units). When closely related fish are bred together particular genes are fixed (the only version of that gene available for breeding in the population). If selective pressures on particular defects are not large, a population can end up with a collection of slightly deleterious alleles of genes. Collectively they may have large effects but incrementally the addition of one or a few new slightly deleterious gene in a generation will not be that strongly selected against. If this affected one percent of the genes, a line could end up carrying 300 slightly deleterious genes. That many would probably add up to having some effects on the fish.

    There are cases of animals being inbred without being all messed up but they require a lot of work and time. The best examples would probably be the many completely inbred (all genes homozygous) mouse lines used in research. The lines generally have somewhat smaller animals which have litters of about 1/3 the size of their wild relatives but (other than specific mutations they carry) are relatively normal.

     

    #351578

    olly
    Participant

    Rüdiger, is female D.margaritatus with break-up of the ‘normal’ pattern on the photo young or old?

     

    Small group of  D.margaritatus (3m+3f) live in my tank from the summer of 2011. Young females had a classic slightly colored anal fin as a female in the profile. Photos February-March 2012.

    female-D_margaritatus.jpg

    female2_march2012.jpg

    This spring, I found that the anal fin of my aged females became colored with break-up pattern. The same females a year later. Photos February 2013. My apologies for very bad pics but coloration of anal fins is seen here.

    Male and female(behind)
    male_femaleFeb2013.jpg

    Female – male – female

    female_male_female2Feb2013.jpg

    I think that in the case of my D.margaritatus the appearance of coloration of anal fin in females is age-related change. Perhaps it is due to the change in hormone levels during aging.

    @mikev said:
    As for margaritatus/erythromicron… it is so common that my feeling that this is “normal” age-related change?

    Yes, potential reason.

     

     

    #351580

    Rüdiger
    Participant

    Hi guys,

    first @BillT, I must apologize, I somehow missed your question! But Charles explained it admirably! ;-)

    @olly I can look up the age tomorrow but I’d say that female is about 16 to 18 months old. Unfortunately I have to throw a spanner into the wheel as far as age as a potetial cause of pattern breakup is concerned. All my specimens, which show aberrant patterning did so from the very beginning, i.e. when they first started to show real color.

    Regards

    R.

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