The Value of Artemia Brine Shrimp
Artemia as a tropical fish food fulfill a valuable need, particularly in the early development of fish fry. By preference, baby brine shrimp, called "nauplii", are frequently used as a first food for newly hatched fish. Artemia are available at the aquarist's command whenever he needs them. The eggs can be stored ready to use for years, and can be hatched within a few hours, whenever the aquarist wants - and the brine shrimp will then swim about for hours, slow enough for even for slowest of fish to catch them easily.
All aquarium fish readily eat brine shrimp, and when included in there diet, these fish have vigorous growth, excellent survival rates, and better resistance to diseases. Compared to any other live food, brine shrimp are superior in being free of contagious diseases and parasites which can attack aquarium fish and brine shrimp can be hatched in pure cultures. These points can only be appreciated by further comparison to other forms of live foods, such as those which require collecting from wild sources in streams, ponds and lakes, the elaborate separating of the netted catches, the desirable from the undesirable, and the running of the constant risk of introducing a host of unseen troubles into the aquarium in the form of fish parasites and disease organisms.
The other alternative to brine shrimp is for the aquarist to culture various forms of live foods, all of which require much space, time and skill - and still the aquarist must run he risk of introducing undesirable organisms into the aquarium while feeding. When all the alternatives to feeding Artemia are considered, these remarkable brine shrimp emerge as one of the best of all live foods for all aquarium fish.
In addition, Artemia are unequalled as a fish food for the early life stages of developing fry, being completely nutritious and of just the right size for all growth stages of baby tropical fish. Even greater use of Artemia can be obtained if the aquarist understands the growth rates of baby brine shrimp and utilizes this knowledge in the feeding at the correct nauplii growth stages to the tropical fish.
Newly hatched Artemia emerging from their protective shells are extremely small, mostly less than 1/2mm in length. At this time they are bite-sized for all aquarium fry except the tiniest of newly hatched egg-layers. Newly hatched baby brine shrimp have rapid growth and may double in size in 20 hours or less. Over a period of a week the baby brine shrimp can increase in size four to five times larger. Therefore, by waiting for the right time after hatching, the aquarist can have the right sized nauplii for baby tropical fish.
Not feeding baby brine shrimp of the right size to tropical fish fry is one of the most common mistakes made by aquarists. This is the reason why one aquarist might report after hatching baby Aretmia that they were too large for a certain species of newly born fry, while another aquarist will report complete success in feeding brine shrimp nauplii to the same species. The successful aquarist had timed the hatch and had fed the nauplii to the fry before the nauplii had become too large for the mouths of the fry.
The aquarist can easily prepare a suitable culture solution in which to grow nauplii of brine shrimp by using water equal in salinity or slightly more saline than used for hatching the brine shrimp. This solution should be placed near strong artificial light, or in sunlight until a slight green growth of single-celled algae develops. The baby brine shrimp, after hatching in the usual manner, may now be transferred from their hatching container to this culture solution. The green water of the culture solution will provide the food source needed by the nauplii. If the container is not overpopulated with brine shrimp, and if sufficient oxygen is present in the water (aeration may be used), the baby Artemia will grow at the rapid rates cited above.
As a pleasurable and rewarding experience, try hatching Artemia brine shrimp, and watch your aquarium fish thrive on this perfect food.
The Other Leaf Fish
There are many popular tropical fish which are rarily bred by aquarium hobbyists. This does not mean that frequent attempts are not being made. Certainly, one of the major stumbling blocks to successfully spawning a difficult species is the lack of information available on how to go about that job. A partial list of those fish frequently found in the aquarium, but infrequently spawned would include:
elephant-noses, loaches, sharks (Labeos), silver dollars, plecostomus, knife fish, butterfly fish, bubblebeefish, and leaf fish. Happily, there is an exception to the rule as far as leaf fish are concerned. The popular species, Monocirrhus Polycanthus, remains a very difficult challange, but the lesser known Polycentrus Schomburgki can be spawned even by the beginning aquarist. these two species of leaf fish come from South America. A third species, Polycentropsis Abbreviata, is native to Africa.
While P. Schomburgki does not present a dramatic profile like M. Polycanthus, there are several qualities to recommend it as a special aquarium resident. The species grows to a length of only 3 inches, so it is not particularly difficult to house or feed. A partial diet of live food is essential, however, if the fish is to be kept in good condition. The best live foods in order of their acceptance are small live fish, young earthworms, tubifex worms, brine shrimp, and daphnia. Frozen foods and dry foods in pellet form will gradually be accepted if the hobbyist learns to "outsmart" the fish. Take the food in queation and roll it up into a small ball. Drop one or two of these balls into the aquarium. If the fish is trained to strike out at whatever hits the surface, it will swallow the ball of food. Should the ball sink, he may refuse to eat it. P. Schomburgki prefers feeding near the water's surface, but it will not abandon a tasty morsal on the tank floor if it offers a particular interest. Try rolling live tubifex worms into a moistened ball of dry food and offering this to the fish. Once the proper feeding habits are instituted, the problem of matching and mating can begin.
The breeding tank for P. Schomburgki can be quite small, a 10 gallon being the best size. Use a fine gravel for the substratum. It should be dark in color, and a natural gravel is best, not a dyed one. Those colored gravels coated with epoxy are completely safe, however. Two inches of gravel offers a sufficient depth.The filtration system should be a small inside filter preferably one of sponge. If primarily live foods are fed, there will be little need for the filter to pick up any real quantity of gross matter. For security and as possible spawning sites, use a small flower pot and several large-leafed plants such as melon swords. Three sides of the aquarium should be covered with a background so that the fish will not be surprised or distracted by external occurrences.
Water conditions should closely approximate those in the wild. P. Schomburgki is found in coastal tributaries of large rivers in Brazil and the three Guianas. This means the water is slightly brackish and usually quite warm. Try to maintain water conditions between the following values:
pH=6.8-7.2; DH=5-15; and temperature=76-78 degrees. Adding a 1/4 teaspoon of marine salt per gallon will help maintain the water chemistry at the proper levels as will changing 50% of the water once a week.
The breeding tank must contain only P. Schomburgki and, in fact, any fish as predatory as this one should be given its own aquarium. Males of the species change from a light brown coloration to a beautiful black accented by iridescent blue-green spots when courting a female or being aggresive toward another male. The females remain light but undergo a slight loss of color when they are ready to spawn. It is naturally more difficult to acheive adequate breeding conditions in the female than in the male. To insure success, once the fish have been kept together and learned a specified hierarchy or community position, the females and males should be separated. Feed the females heavily for two weeks and watch closely for signs of the breeding tube which will become visible when the female has produced sufficient eggs to spawn. A slight bulging of the stomach will confirm an abundance of eggs. Now, take the male which dominated the mixed tank and a female which seems compatible; place them in the breeding tank, turn the filter down to a small trickle of air, and wait for results.
P. Schomburgki display certain behavioral traits normally assigned to cichlids. The male will stake out a territory and select a spawning site within that area. He will defend this against all intruders including the female. Spawning takes place only if he is satisfied with the female he is offered. If a rejection occurs, the female must be removed and another substituted. The male will butt the female gently in the vent area and attempt to attract her to the spawning site. The fish may spawn on the underside of a leaf, a flower pot, or a rock ledge. The female attachs the eggs to the spawning surface and the male releases sperm which floats upward to fertilize the eggs. This corresponds to the substrata spawning sequence of many cichlids; first, a run by the female during which the eggs are laid; then, a run by the male when the sperm is released. The female is upside down when attaching the eggs but the male never assumes this position.
After spawning, both the male and the female should be removed so that live food will not be introduced into the tank. At this time, aeration should be increased. After two days the eggs will hatch, and after 7 days the fry will be free-swimming. At 6 days it is best to begin feedings. The sponge filter will come in handy as a feeding site for young fish looking for a between-meal snack, and the fry cannot be trapped in the filter. As first foods, feed brine shrimp nauplii and finely crushed dry food. Later, tubifex, white worms, and daphnia can be fed. The fish will grow rapidly for several months but the rate will reach a plateau after which growth is steady but slower.
Killifish in the Aquarium
Killifish belong to the family Cyprinodontidae which is more or less restricted to tropical and sub-tropical climates throughout the world. These fish are often referred to as egg-laying toothcarps. This descriptive title suggests the carp-like characteristics of killifish. They differ from carp in that they possess teeth on the borders of the jaw and pharynx. As a rule, they are small fish. The average size is 2 inches, with a few species growing to 5-6 inches. At one time, popular livebearing fish of the Poeciliidae family (and other related families) were merged into the Cyprinodontidae family. These livebearers are known as livebearing toothcarps and are closely related to their egg-laying relatives.
It is not unusual for the beginning hobbyist to be attracted to this beautiful group of fishes. They have, from all external appearances, every positive quality that could be desired. Often, however, the novice is warned that killifish are difficult to maintain and only advanced aquarists can be successful with them. This is by no means an accurate statement. With limited study and thoughtful preparation, any hobbyist can keep and breed these fish.
There are many genera of killifish which are kept by aquarists. Some of these include:
Aphyosemion, Nothobranchius, Epiplatys, Cynolebias, Aplocheilus, Pterolebias, Rivulus, Roloffia, Fundulus, Pachypanchax, Cyprinodon, and Aphanius. The general maintenance of all these fishes is very similar, while the breeding techniques vary considerably.
Killies do not require large aquaria and it is best to keep only a pair or trio together. For most species, a 2 1/2 gallon tank is of sufficient size. Those fish which are larger or more aggressive should be given 5-10 gallons of tank space. If young fish are being raised to maturity, many can be housed in the same tank assuming they are approximately the same size. These rearing tanks should be 15-30 gallons. Glass tanks are recommended for use with killifish since they are completely inert and can add no dangerous substances to the water. Also, they tend to remain leak-free through frequent periods of "use" and "disuse".
Gravel has little place in killifish aquaria. If it is used, care should be taken that it is a natural or coated variety which can release no harmful chemicals. Carefully washed peat or silica sand make the perfect substrata. If rooted plants are to be used, they can be anchored in a layer of peat covered by a layer of sand. Cryptocoryne make excellant bottom plants, as do Hygrophila, Limnophila, and Hydrilla. The best plants are those that float in the water or on the surface of the water. These include Lemma, Nitella, Riccia, Vesicularia, Ceratopteris and Myriophyllum.
Proper lighting is a very important consideration for the killifish tank. Certain types of lighting can be harmful to killie eggs, and breeding occurs best under minimum lighting conditions. Low wattage incandescent bulbs provide adequate lighting. If fluorescent tubes are employed, the "warm white" type is best.
Aeration and filtration are very important to the small aquaria. Water conditions can change drastically in a short time if overfeeding occurs. The sponge filter offers a perfect solution for the killifish tank. It can be used in breeding tanks, hatching tanks, and rearing tanks with little worry that small fish will become trapped in the filter. In addition, it provides a feeding site for young fish. The inside box filter also has a positive feature; peat can be placed in the filter to release natural chemicals into the water. This produces a tea-colored effect which aids in reducing light penetration. Should a filter not provide adequate aeration, an airstone must be employed.
Careful control of temperature is necessary in the killifish aquarium. Unlike most tropical fish, these fish should be kept below 75 degrees. The optimum temperature range is 70-74 degrees. Killifish which are continually maintained at high temperatures will be more susceptible to disease and have a shorter life span than normal. At 81-82 degrees, the metabolism of a killifish is so high that almost constant feeding is necessary to assure good health. It is strongly recommended that the fish room of the killifish hobbyist be centrally heated as it is difficult to control temperatures accurately in small aquaria with themostatic heaters. Also, many hatching tanks are merely small containers which cannot be heated by standard aquarium heaters.
It is advisable to keep covers on aquaria containing killifish. They are excellant jumpers and can find their way through even the smallest hole. Floating plants will restrict jumping only to a limited degree.
Water conditions in the killifish aquarium must be carefully controlled. Monitoring of various chemical indices is a regular and necessary part of proper maintenance. For many years, great emphasis was placed on keeping killies only in acid water. This was gradually proven to be an error propagated by inadequate investigation. Killies should generally be maintained in water with the following values:
pH=6.8-7.2, DH=less than 5, and very low CO2 levels. Should the fish be direct from the wild, every effort must be made to reproduce the chemical content of the natural waters. Sudden or extreme changes in water conditions can be disastrous to even the hardiest of killies. It is advisable, however, to make frequent water changes in the killie tank. At least 1/3 of the water should be changed every week. If it is difficult to keep water hardness at low levels, then rain or distilled water can be mixed with normal tap water.
Although basically carnivorous in nature, killifish will learn to eat almost any food they are offered. While live foods give many benefits to the fish, in the aquarium it would be a mistake to believe they can offer all the nutritional elements required. When flake or frozen foods are first introduced, it is a good idea to place "conditioned" fish in the aquarium to show the new fish what they are missing. Only a few "lessons" are necessary before the fish learn to eat. There is a wide variety of live foods which killies can be fed. These include:
brine shrimp, daphnia, tubifex worms, white worms, fruit flies, mosquito larvae and bloodworms. Killifish fry must be fed smaller live foods such as
brine shrimp nauplii, microworms, and infusoria. It is important to feed killies frequently (3-4 times a day, if possible), but be extremely careful not to overfeed, as small tanks can become easily polluted.
With regard to breeding habits, killifish can be divided into 4 categories:
top-spawners, plant-spawners,bottom-spawners, and peat-divers. The breeding tank for each of these types should be prepared with care to provide the proper accessories. Top spawners are those species of killies which prefer to spawn very near the water's surface. In some cases, eggs can be found out of the water on top of plants. Fish of the genera Aplocheilus and Rivulus are the best known examples of top-spawners. Plant-spawners are those killies which breed in plant thickets found in mid-water or just above the tank floor. Representatives of this group include most Aphyosemion, Aphanius, Epiplatys, Fundulus, and Pachypanchax.
A very clever device is used in spawning both top and plant-spawners. It is called a spawning mop and is made of nylon yarn. The yarn should be boiled before using to remove any excess dye. Yarns made from organic substances such as wool or cotton will gradually rot away and may add harmful chemicals to the water. For the top-spawners, these spawning mops must be allowed to float. This is accomplished by attaching them to a cork. Plant-spawners will spawn in either floating mops or those anchored to the bottom of the aquarium.
Bottom-spawners will spawn directly over the substratum. Either fine silica sand or peat may be used. Often, the eggs are buried by the fish. While this is strictly coincidence, it may be advisable to leave them covered as they are better protected from light, bacteria, and hungry fish.
Pet-divers are a variation of bottom-spawners. Their spawning behavior is unique in that a pair will dive into the substratum and completely bury them selves during the spawning process. Obviously, material for the bottom soil must be very soft and non-abrasive.
The incubation periods and methods of incubation for eggs of the various groups of killifish are considerably different. The top-spawners and plant-spawners produce eggs which hatch in 10-20 days. These eggs are water-incubated. They should be picked from the spawning mops every 2-3 days and placed in a small plastic container which is filled with water from the breeding tank. There is no need to worry about damaging eggs when they are picked since they are protected by a tough shell. The temperature in the hatching container must not rise above 74 degrees as excess heat will cause the eggs to hatch prematurely. Newly hatched killifish have absorbed all their yoke sac so they must be fed immediately.
There are two basic types of bottom-spawners. One group produces eggs which must go a "drying-out"period. These fish are true "annuals" for the bodies of water they inhabit dry up at the end of each rainy season. The genus Nothobrachius is the best known bottom-spawning annual. The eggs and spawning medium (peat) are dried to the consistency of pipe tobacco and placed in a sealed plastic bag. Complete development takes 2-3 months. When the eggs appear ready to hatch , place the peat and eggs in a container filled with water from an established tank. In order to assure a uniform hatching agitate the water and add a small amount of dry food.
Certain species of the bottom-spawning group produce eggs which may be either water-incubated or peat-incubated. This indicates that the areas in which these fish are found do not always dry up on a seasonal basis. These fish include many Aphyosemion, such as, A. Walkeri, A. Coeruleum, A. Arnoldi, A.Nigerianum and A. Filamentosum.. The peat incubation method is recommended for these eggs since less work is necessary to prepare the eggs for hatching.
Peat-divers are restricted to the South American genera of Cynolebias and Pterolebias. These fish are true annuals with eggs which may develop in as short time as 2 1/2-3 months or remain in a "resting" state for several years. When hatching eggs from these fish, only those which show clearly defined eyes and a dark embryo should be selected. The others must be held for future observation. The eggs, of course, are peat-incubated.
Although the information presented above is only a brief synopsis of how to maintain and breed killifish, it should be of help to anyone wishing to keep these "living jewels".
Hints for Hatching Killifish Eggs
With the exception of a few species, killifish will spawn with regularity, depositing a few eggs daily in the spawning medium provided. A synthetic mop, made of nylon or acrylic yarn, has proven to be the most practical medium for the plant spawners, e.g., most species of Aphyosemion and Roloffia. The eggs can be easily picked from the mops and then water incubated in small containers. (The eggs are very soft when first deposited and they should not be picked until they have had time to harden.) Because of the long incubation period of killie eggs - 2 weeks for most plant spawners - they are quite susceptible to attacks by fungus and bacteria. The greatest challenge to the breeder is to provide an adequate environment for the incubation of the eggs.
If water incubation is used, some type of fungicide or bactericide should be added to keep the water sterile (acraflavine is frequently used). Infertile or infected eggs should be removed daily to prevent the good ones from going bad. After 3 or 4 days, it is not necessary to check daily, except to observe egg development and to look for fry.
If water incubation proves to be unsuccessful, and it is certain that the eggs are initially fertile, many hobbyists will incubate the eggs on top of peat moss, a method that reduces the possibility of infection. The peat moss should be boiled before use and then packed - a thin layer will do - into a small container such as a petri dish. After the eggs have been placed on top, the container should be covered with a lid to avoid excessive evaporation. Eggs can be collected and placed in water and then transferred with an eyedropper to the peat moss. It is important that the eggs do not touch each other, so as to reduce the chances of them becoming infected. After the eggs are fully developed, they can be placed in water for hatching. Although the incubation time, on the average, will be longer using this method, it is often successful when water incubation fails.
Quite often killifish eggs will not hatch naturally and the embryos will eventually die. If eggs are fully developed, they can be "force hatched" by increasing the amount of C02 in the water. You can do this by placing the eggs in a small vial, blowing into it, and quickly replacing the lid. All of the eggs should hatch within 2 to 4 hours.
Another hint that can help avoid frustration with these lovely fish is to add a teaspoon full of rock salt to every 2 gallons of water. This will insure that velvet, the most common killifish disease, will not be able to make any headway. Healthy fish are the key to egg production.
