Success With Killifish
by Ed Warner
Reprinted with permission of Ruth Warner

The first three chapters of Ed Warner's popular and highly recommended book are below courtesy of Ruth Warner. These chapters are provided to assist as an introduction to beginners as well as to provide a taste of Ed's common sense approach to keeping killies. The entire book with color photographs may be ordered direct for $10.00 postpaid. Contact Ruth, Ed's wife, at:

Ruth Warner
1512 Lilac Lane
Machesney Park, IL 61115(815) 877-8847

Or visit her web site at


  1. Introduction
  2. Accommodation
    Water Condition
    Aeration & Filtration.
  3. Receiving Fish
  4. Breeding
    Mop Spawners
    Peat Spawners.
  5. Raising the Fry
    Food for Fry
    Algae Substitute
    Freshly Hatched Brine Shrimps
    Hatching out Shrimp Eggs
    Live Adult Brine Shrimps
    Grindal Worms
    White Worms
    Glass Worms
    Mosquito larvae
    Tubifex Worms
  6. Accidental Hybridization
  7. Questions & Answers
  8. Killifish Species

Appendix A. Incubation Time
Appendix B. Incubation Solution
Appendix C. Spawning Mops
Color Plates

@1977 Edward Warner Palmetto Publishing Co. St. Petersburg, Florida. All rights reserved. No part of this book may be reproduced in any manner without the prior written consent of the publisher.

Mini Pet Reference Series No. 1.

ISBN No. 0-915096-02-1


To my wife, Ruth, who has given up many things in life because of my fascination and devotion to tropical fish.


This book may well seem to be unusual in that it has no Acknowledgments or Bibliography There is absolutely no material obtained from other sources, or gleaned from the writings of other authors. Any errors or unintentional false statements are my fault, and mine alone.

The background information that is the basis of this book, was obtained by personal involvement with tropical fish over a period of some 22 years, and specifically 12 years breeding Killifish, therefore I suggest that I am well qualified to write authoritatively on the subject.

My 'workshop' consists of over 200 tanks, all of which contain fish. Add this facility to the countless number of experiments that I have performed and distill it into the pages of this work and I am certain that the final result will prove of great help to other aquarists interested in pursuing this particular avenue of fishkeeping.

There are other books on the subject, but the majority of these are restricted to the old original information, with the same inaccuracies being carried on year after year. Also, when authors research information for books containing hundreds -of species, these inaccuracies find their way into the new books. Anyway, that has been my experience.

Please remember that all my work was executed in my hatchery at Rockford, Illinois. It may well be that the methods that worked for me there will not always work for you in Great Britain, Florida or Oregon, or in some other part of the globe. Use this book as a guide. If you have been unsuccessful in breeding a certain fish, or raising the fry, start by using my methods, or incorporate part of mine with ideas of your own.

If this book has helped to further the cause of good fishkeeping then the purpose of this book will have been fulfilled and I will be content.

Edward Warner., jan.1977.

1. Introduction

Most hobbyists who have become interested in Killifish are aquarists who have had some previous experience with other species of tropical fish, and who now wish to expand their knowledge by entering the fascinating realm of the 'Killies'. The purpose of this book is to guide the experienced aquarists and those aquarists who are venturing forth for the first time, along the path to successful Killifish husbandry and breeding.

When the author started keeping these attractive 'pond fish' there were about 180 known species, now there are over 750! It is obvious that a book of this nature could not possibly do justice to over 750 different fish, however, it is possible to cover those species usually available, and to proceed without too much difficulty The Killifish field is growing so rapidly that any book published on the subject is more or less out-of-date before it reaches the aquarist.

A point that cannot be stressed too strongly is that the beginner should not be discouraged if he fails in his initial attempts to keep or breed these fascinating fish. Please do not start with the most difficult species, start with the easier species and then when you have had some success with them, graduate to the more difficult ones. Remember, a Boy Scout who has just completed a First Aid course is not ready for brain surgery

This book has been designed to progress naturally through the various facets of keeping and breeding Killifish, it is a practical work, academic considerations have been more or less omitted intentionally since this information is available in other publications should it be needed. However, it is of interest to know something about the group of fish known as Killifish.

The name Killifish is derived from the Dutch word 'killi' meaning 'small pond'. Small ponds are the natural habitat of these fishes. Killifish have also been known in the past as Panchax.

The name is somewhat misleading, since it implies that these little fellows are fierce, and spend their time seeking and killing other members of the aquarium. This is, of course, just not true. Maybe some enterprising taxonomist will decide on a more appropriate name in the future.

Killifish belong to the family Cyprinodontidae, and they are often described as "egg laying tooth carps". They are closely related to the "live bearing tooth carps" which includes the Goodeidae, Poeciliidae, Anablepidae, etc. The main difference being the latter males have an external sex organ which is absent in the Cyprinodontidae.

The genera are:

Aphaniops Jordanella
Aphanius Leptolucania
Aphyosemion Nothobranchius
Aplocheilichthys Oryzias
Aplocheilus Pachypanchax
Chriopeops Proftindulus
Cubanichthys Pterolebias
Cynolebias Rachovia
Cyprinodon Rivulus
Epiplatys Valencia

A good representation from these are found under the heading 'Killifish Species'. Now some of the above are very rare and in some cases perhaps extinct. Others, like those of Cyprinodon genera, commonly called "Desert Pupfish" are on the Endangered Species List and collecting, harboring and possession of these fishes is a violation of a Federal law with stiff penalties.

2. Accommodation

Any of the standard sized aquariums are perfectly satisfactory for keeping Killifish for show, but for breeding purposes, small aquaria are advised. The reason for the small tank is to keep the fish in close proximity; every time the male fish turns, the female will be nearby, and the mop or peat waiting to receive the eggs. If a pair of Killifish are put into a 10 or 20 gallon tank, they will only have a passing relationship, and if the mop is not handy at the critical moment of spawning, then the number of eggs will be greatly reduced.

For the smaller Killifish, a 6 quart oblong bowl is sufficient. For the larger species, such as the Blue Gularis, use a 2 1/2 gallon tank.

Freshly hatched fry can be placed in plastic dish pans for a week or two and then placed in 5 gallon or larger tanks to mature. When using plastic dish pans it is important to change the water daily, or at least, every other day, to prevent water pollution, which is the number one killer of fry.

When raising the fry to adults, use long tanks rather than deep ones. The fish seem to fare much better in this shape of tank, with the reduced depth of water and the consequent reduction in pressure. The air pumps are more efficient also since they do not have so much weight to lift.

The author does not supply any filtration or aeration to the small tanks containing the breeding pairs, but it must be remembered that he feeds only live foods. However, their water must be changed every week or two anyway, so in the author's opinion, filtration is unnecessary.

Killies are great jumpers, and they do not like strong light. For this reason hoods with lighting strips should not be used. The author uses screened tops made with aluminum screening stapled to a wood molding. (see sketch) This is an inexpensive device, easy to make, and has the virtue of being very effective.

Killifish will lose their color if they are put into aquaria that have light-colored gravel covering the base, therefore black or very dark gravel is recommended. Some individuals paint the outside surfaces of the back and sides of their tanks to give their Killies a greater sense of security Killies will also lose their color if they are placed in bare tanks without any gravel. For this same reason, Killies housed in bowls for show purposes rarely do well.


Water conditions are really not as critical as many aquarists would have us believe. This is supported by the fact that the author has raised many Killies in hard alkaline water when books advise the use of soft acid water. But it is important to make all water changes gradually Use about 1/4 hard water and the rest soft water so that the resultant water is medium hard. This 'average' water allows the fish to be acclimated to any type of water easily

Water drawn from a domestic faucet will undoubtedly contain traces of chlorine and copper ions. The chlorine is added to purify the water and the copper is absorbed from the piping. Chlorine can be removed by using 'Start Right" or 'Clear Holdex". (When I mention a certain product name it is because I use it, although any SIMILAR product will do as well, of course. No commercialization is intended. Ed Warner.) 'Blue Holdex' turns the water an ugly green when used with peat. Alternatively a few drops of pure sodium thiosulfate will do the same. Copper can be removed by filtering the water through activated carbon, but this should be done before any peat moss is added to the water, peat moss releases substances which are absorbed by the activated carbon and the result is that they effectively neutralize each other.

If the soft water is obtained from a water softener, do not worry about the presence of sodium ions, they will not affect the fish one bit. At times the author has used only soft water and the fish live and breed just as well as when it is mixed with hard water. With the mop spawners use one drop of Methylene Blue per gallon of water. The reason for the blue coloring is twofold: most Killies prefer the dim light, and since their eggs are light sensitive, the Methylene Blue serves a dual purpose.

Now this is very important. ALWAYS use a salt ratio of four (4) teaspoons of non-iodized salt per 10 gallons of water. This goes for the breeders, eggs and fry Remember to add the proportional amount of salt when making water changes, either partial or complete. Persons who live in areas where they can draw their water from lakes should use salt at a ratio of one teaspoon per gallon of water because Velvet (Oodinium) is almost always present in this water and you will find it almost impossible to maintain the Nothobranchius species without the salt.


It has already been stressed that Killifish prefer dim lighting conditions. It is an important factor, so no excuse is made for the repetition here. Hoods with strip lighting are not recommended, but if the aquarists does use such a method for lighting his tanks, the wattage must be of a very low order. It is preferable to use no special lighting, normal room illumination is sufficient.


As stated previously, the author does not use any aeration or filtration in tanks containing breeding fish, the reason for this is that he only feeds live foods and changes the water frequently The same applies to fry maintained in plastic dish pans. However, in tanks where one would normally house adults or fry, filtration must be suitable. Any filter that is strong enough to suck up the fry is obviously unsuitable, but a filter packed with charcoal and filter floss, even if it has a good rate of flow can be used successfully in tanks containing adults or half grown fish.

Undergravel filters can be used when there is no danger of losing fry In fact, it would be safe to say that any method of filtration or aeration may be used with Killifish that would be used for other tropical fish. Remember, undergravel filters have a tendency to slowly acidify the water if water changes are not made periodically

3. Receiving Fish

This procedure is sound for all tropical fish, including Killies. A great many fish are lost or disease organisms are brought into tanks when the proper method of releasing fish is not employed. By now, most hobbyists know they should not float their tightly sealed bags in their tanks.

When fish are obtained, either through the mail or direct from a dealer, use the following method. Open the top of the bag and float the bag in the tank where the fish are to be housed. Ad about 1/4 cup of tank water to the bag every hour or two. Continue to do this for 4 or 5 hours. It makes no difference what the pH or hardness of the water is in the bag, since you are slowly acclimating the fish to your water. Many hobbyists want to know the pH or hardness of your water when you ship them fish. What difference does it make? None if you follow this procedure. Now after the 4 or 5 hour period, dump the entire contents of the bag into a bowl or pail and immediately net the fish and put them into the tank from which the water came. In this way, the fish will not go into pH shock and will be ready for their new home. UNDER NO CONDITION ADD THE DEALER'S WATER TO YOUR TANK. If you do not already have disease, why contaminate your tank with some else's water? It is perhaps better not to feed the new fish for the first 24 hours; they need to become familiar with their surroundings and settle down a bit after being tossed around in a bag for some time. If you have an extra tank available for quarantine purposes, it would be advisable to use it. But in any event, use the method detailed above and your losses will be minimized.