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  by James K. Langhammer

(This article was first written in 1986 and appeared in LIVEBEARERS #87. This 1999 version is an update and adds new information.)

Aquarists are confronted today by the grim prospect that their hobby may be self limiting to the extent that it may eventually falter and extinguish itself.  In our throw away consumer society, wherein replacement seems always the preference rather than maintenance and repair, aquarists seem also plagued by the mentality that newer is better. New imports are the vogue and the fishes you saw at last year's shows are often déclassé' today.  The amazing aspect of this is that at one time wild guppies, neon tetras, and convict cichlids were as exciting to aquarists as the golden Sailfin goodeid,  the dwarf neon rainbowfish, and Rift Lake cichlids are today. Aquarists are often so snobbish that some have never kept the “older” favorites. Other aquarists are so naive that they fail to recognize an exciting "new" fish is a reimportation of an older favorite, which a past generation of aquarists allowed to die out!

The habitats and wild populations of many species are disappearing  forever. Populations of such easily maintained aquarium species as Skiffia francesae, Cynolebias whitei, and Barbus nigrofasciatus may already be extinct in the wild.  For such a species, there will be no reimportations if captive stocks are lost! William Beebe, a famous naturalist, once wrote: “...when the last individual of a race of living things breathes no more, another heaven and another earth must pass before such a one can be again.”

Individual aquarists and, more importantly, aquarist organizations must accept the challenge that Species Maintenance Programs need to be implemented NOW! Goals and attitudes need to be changed.  Aquarists should not be praised and envied for their expensive "new toys". Rather, I suggest that the faddish aquarists should be educated to the importance of using their skills to breed and maintain species over a long time. Breeder Award Programs have helped tremendously 1) by sustaining stocks locally, 2) while distributing fishes widely, and 3) by rewarding aquarists for reproducing fishes.  But in small organizations, there is always the risk a species may  disappear after everyone has worked with it.

Neither one aquarist nor organization can accomplish the task of species maintenance - there are too many imperiled species.  But collectively, WE can do it! and, I offer the  following  guidelines  to  successful species maintenance.


Be   reasonable in your project scope.   Evaluate your own capabilities after all, you know yourself best. Be honest! How dedicated are you to the hobby?  Are you a faddist, by nature? Can you discipline yourself to keep 1, 2, 5, or more species reproducing for at least five years?

Don't be overzealous or you'll burn out. Leave yourself energy and facilities to also play with new fish or specialty fishes (e.g., fancy strains of livebearers, bettas, or angelfish). Perhaps 25% of your facilities could be dedicated to species maintenance. If so, call attention to your goal label the tanks as a reminder to yourself and as  a  prideful  statement to visitors of  your commitment to species maintenance.

Join a group or make friends even by mail or on the Internet with other people who are interested in the same fish.  Cooperation and competition are both healthful adjuncts to your long-term involvement.


The choice of species to be kept is very critical.  Don't be an elitist here either! Not everyone should concentrate on only the MOST endangered species.  Our hobby should divorce itself from the need to import wild fishes in general.  Normally, one importation should be able to establish a species or a unique population within captivity hopefully forever!

When feasible, working with a group sharing similar goals is desirable here.  Each species should ideally be kept by at least three different parties; but for fifty people to keep it whereas another species is NOT kept by ANYONE is counter productive to our goals.

Try to deliberately keep one species that no one else wants. Maybe it is "mean", "ugly", "too big", or  "too small” but it does need a friend and a home. Aquarium societies would be wise to establish rewards or special recognition for such selfless dedication by aquarists. The hobby should recognize these people as our true elite!

For safety in the preservation of genetic purity, it would be best not to keep closely related species.   Everyone has experienced “that” fish which mysteriously appears far from "home" having jumped or been carried by accident in a net or jar to another tank.  Many fishes are transferred accidentally by aquarists who habitually dip brine shrimp or daphnia nets into one tank after another; always shake out such live food ABOVE the water line for safety's sake!  Disastrous hybrids could totally destroy your effort and might wipe out the integrity of a whole species if stock is exchanged in the future!

Remember that taxonomy is terribly imprecise.  Generally you can expect species within a genus to be capable of inter-hybridization, but many genera can hybridize as well!  And because even family status is subjective and not always uniformly applied, don't be too confident that traditional family lines can't be crossed by hybridization.


Depending on an aquarist’s involvement and dedication in the hobby, there may be one to perhaps ten or more aquaria devoted to species maintenance.  While remembering the potential for - as well as the dangers of hybridization, an aquarist may judiciously choose several unrelated species for maintenance in a single aquarium.  Ideally, any species maintenance tank should be as large as possible but probably never less than twenty gallons.  Tanks that are too small may pollute quickly and may also cause increased social pressure on the residents; even non territorial species exhibit some aggression occasionally.

I have had good luck housing together reproductive colonies of Brachyrhaphis rhabdophora and Ilyodon xantusi in a 55 gallon tank; of Goodea atripinnis and Priapella compressa in a 55 gallon tank; and Skiffia bilineata and Heterandria Formosa in a 20 gallon long tank. For each species, birth and growth to maturity occurs regularly in the tank and a regular surplus is produced.

Never house closely related species together, OR above or below one another, OR next to one another.  Ideally, they should be widely separated if kept in the same room to minimize the risk of accidental mixing.


These may be the most important tools in long-term management.  We  all  presumably love our fish and hate to be callous or hard hearted. Yet in a way we are “gods”! Malevolence or benevolence are subject to interpretation. An old saying of which I am fond is "a weed is a flower in the wrong place".  All nature lovers routinely kill plants and animals either deliberately or inadvertently.  What is important, I think, is the reason.  I always cringe at euthanizing an  animal that  I  have  cared  for;  yet  I probably kill a million brine shrimp a day by feeding them to my  fish.  Is there really an ethical or moral difference?

Species maintenance will require optimal conditions to be successful in the long run. An aquarist simply must be practical in his methods. Reasons for culling include:

1. Tanks must not be allowed to overpopulate.

2. Breeding stocks must be kept young to maximize reproduction.

3. Defective fish must be removed to safeguard against possible genetic problems swamping your gene pool remember spontaneous mutations do occur; most mutations reoccur repeatedly with a mathematically known frequency.  Your colonies are not going to be genetically stable just because you never introduce new stock!

For some fishes, surplus stock is readily marketable.  The soft‑hearted aquarist is saved the unhappy chore of euthanizing healthy fish.  But, please, don't only choose species with high marketability or our goal of overall species maintenance will be destroyed. Sometimes, a satisfactory solution is to keep a large piscivore as a pet, which eats your surplus fishes.  Dr. Joanne Norton had a Mata Mata turtle for this purpose; other aquarists keep Oscars or other large cichlids.

As your program proceeds, culling of fish will encompass more than the removal of adult, defective, or sick fishes. From among surplus fishes, a choice must be made which will go and which will be retained for brood stock.  Generally, the best choice is to keep the TYPICAL fish.  We want species maintenance, not strain development! If you always pick breeders subjectively the biggest, the smallest, the prettiest, etc. - you will create domestic morphs that are not even remotely typical of the wild creature.  Remember that Saint Bernard’s and Chihuahuas were once wolves!  Our purpose here is to retain a wild phenotype.

Never be afraid to intensively inbreed your stock.  If you cull carefully and retain your average  fishes for breeders, no meaningful genetic disintegration will occur.  An absurd blanket condemnation  of inbreeding is commonplace today that cannot be proven analytically.  The subject is long and detailed beyond the scope of this article.  Most criticisms of inbreeding were actually based on problems of  poor husbandry.  A change in conditions usually corrects the population problem in the next generation.

Loss of genetic diversity is certainly a probability among inbred fishes. Whenever a closed population of any organism exists, selection and genetic drift will likely permanently reduce the genome. What often is not accepted is that by the time a population in the wild is ENDANGERED, it often has been through a genetic bottle-neck and already has limited genetic diversity in the wild. Unless you know that genetic diversity actually exists, do not just assume it does! There are many highly inbred populations of mammals, birds, and fishes that do not show the deformities, disease, and loss of virility that the doom-sayers prophesize! Ask any Zoo or institution why they do not sustain more endangered species than they do. The answer always is COST! To maintain multiple genetic stocks with maximal genetic diversity for a few species while letting other species become  extinct is abhorrent to me.

Be honest! Would you not prefer to see every species retained as a homozygous colony than a handful of representative species maintained with “partial genetic diversity? “Partial” you ask? Regardless of the platitudes of those opposed to inbreeding, the managers of so-called outbred stocks regularly cull examples of genetic diseases, unusual morphs such as “short-legs”, aberrant pigments, and other atypical phenotypes which are natural components of “true genetic diversity”. They also minimize the simple truth that mutations regularly occur and even reverse themselves. If we save a species into the future as an inbred population, it has the very real potential to some day evolve into a diversified genome again! An opportunity not available to an extinct species!

Sick  fishes are of course best euthanized and discarded.  Since fish are cold blooded, gradually lowered  temperatures are not painful nor traumatic as they are to warm blooded animals which experience thermal trauma.  An easy death for fish (and for the aquarist!) is to bag the fish in its tank water and then to set the bag in a freezer.  The fish's metabolism simply slows down bringing stupor and death without apparent trauma.

I  manage  my colonies by never allowing breeders to remain more than one year after reproductive maturity. For most livebearers, removing all adults once a year in the Spring is a good  program and  can save a lot on the food bill.  Young fish quickly mature and reproduce during the lengthening day light and a  whole  new generation revitalizes your colony.  Some fish  (e.g., large cichlids and catfishes) may require more than one year to become reproductive but once they do, move out the older generations.  Train yourself to love the species and protect its long range welfare, rather  than  being  impractically  attached to individual fish. It frequently happens that when an aquarist keeps older breeders, one day the colony becomes senescent and reproductivity is lost!

Remember my point back in "1. Define Your Goals"?  KNOW YOURSELF;  you can pamper  yourself  by  keeping some personal pet-fish but do so in aquaria external  to the project. You do need to enjoy the hobby to stay in it! So don’t stagnate. Revitalize your interests in any way necessary!


Many of you are better persons than you perhaps believe. In our society self denigration is commonplace. I'm not sure why but rarely do people appreciate and value their self worth.  It is common to hear:  "...but  I'm not as well educated", or "...she's more skilled", or "...he's a professional". Never forget that education is only the formal molding of the innate intellect; that skill is only the overt expression of latent talent; and that a professional is paid, an amateur is not  there is no inherent implication of skill or intellect in either title. A professional can be incompetent and many amateurs within their field are without equal.  An expert can be either  professional or amateur,  so strive to become expert in your interest.

Challenge yourself to read, to observe, and to keep records. The small scale aquarist has unique opportunities to grow beyond the boundaries of a limited fish room.  Your time is less divided than is the case for someone with too many charges.  The quality and quantity of care is probably greater within your small set up.  You can become  a competent  and  respected aquarist in spite of limitations.  The late Braz Walker, one of the hobby's most respected authors  and aquarists,  became so while a quadriplegic restricted to a respirator!

Never underestimate yourself.  Don't  hesitate  to  approach  an expert  for help.  Friendly people are friendly and unfriendly people are unfriendly regardless of occupation.  Some experts are very cooperative and will  help you  as  much as they have time for.  Obviously they cannot drop everything for your immediate needs; to expect this, casts you in a bad light, not the expert.  Curb your impatience the wait can often be rewarding.  Experts recognize sincerity  but  don't expect them to be your mentor.  Do your groundwork.  Prepare intelligent, concise questions and keep them to a minimum at any given time.


Sharing is one of the most rewarding aspects of our hobby. New and often lifelong friendships can be made by being sincere, generous, and friendly.

Sell or trade your surplus at reasonable rates; or even give them away outright sometimes, future reciprocal gifts can be very rewarding.  Don't overprice the rare species it  probably cost the same to raise as the common species in reality. Ideally I prefer to give away endangered species in order to broaden their base of existence as much as possible.

In the event you close down your maintenance of a given species, be as responsible as you can in relocating your  stock.  Try  to find a recipient who will have a long term commitment. What ever you do, don't just abandon your past commitment to safeguard the species.  Some Zoo  professionals today prefer to euthanize surpluses of endangered species rather than to allow private amateurs to work with them. I am not referring to dangerous species that are ill suited to home  management,  but small  birds,  fishes, herptiles, and mammals.   Such irresponsibility by those professionals is not furthering species maintenance.  Amateurs generally have better track records  than Zoos with small animals; they are simply better cared for in the home environment  than  by  the average apathetic, 40 hour/per week public servant. Usually the best Zoo track records for species maintenance are where the staff members were previously  amateur  hobbyists  who brought  their PRIVATE expertise to the Zoos.  I'm not saying to indiscriminately distribute your stock  but  don't  hesitate  to give  a  sincere person a chance to get involved.  We all had to start somewhere.

Publish your experiences or, when possible,  give verbal presentations.  Question and answer sessions rarely “flow” only one way usually both parties can learn something.

Remembering my  "5. Grow  in  Stature"  premise,  communicate  with others. You will be surprised at the professional zoologists who are  ignorant  about good husbandry practices and need help with research programs.  Many in-house laboratory programs had to be curtailed due to government-funding cut backs. Some professionals request amateur involvement in on going  research programs.  In  return,  you may receive access to libraries, lab equipment, or personal knowledge.

Don't be guilty of being close mouthed. There should be no hobby secrets. Success is usually a measure of constant care and not a secret method.  I'm afraid I have no respect for the concept  of patenting, copyrighting, or refusing to share methods. I suppose a  fine  line exists between the commercial need to protect a service or product and between our own  situation  as  concerned aquarists.  Nonetheless, I respect cooperation and generosity as a sign of a truly great aquarist.

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I hope you'll take my suggestions to  heart.  Our wild species need all the captive support we can give to them.  Remember that this program will work best if you leave room for your own self gratification.  Just as total abstinence from sweets and fattening foods is less successful than moderate intake during a diet -  a careful balance of your priorities between  keeping  fun fish  and  maintaining one or more species may allow you to indulge your whims - while simultaneously  improving your image as an aquarist!.

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i wish to thank j.langhammer and the ALA for their permission to use this article on the livebearers website