[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Freshwater Fish – Killifishes

Directory of Freshwater Fish

Killifishes

These narrow-bodied, often highly colorful fish deserve to be far more popular. Their small size means that they do not need to be accommodated in a large, expensive tank. In addition, many of the more widely available killifish are easy to maintain, and they can often be persuaded to spawn in home aquariums. Their main drawbacks are that some are highly aggressive toward their own kind, and, since they feed naturally on small invertebrates in the wild, it can be difficult to wean them onto substitute diets. Sexing is simple, since the fins of the males are more pointed than those of the females.

Common Lyretail (Aphyosemion australe)

• ORIGINS: West Africa, found in parts of Gabon, Cameroon, and Zaire.
• SIZE: 2 1⁄2 in (6 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 64–75°F (18–24°C); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Peaceful and social.

Male Common Lyretails are much more brightly colored than females and have pronounced caudalfin rays that give the tail a lyrelike shape. They need a slightly brackish environment and a densely planted tank. They are usually kept in a singlespecies setup, partly because their small size limits the choice of tankmates, but also so they do not hybridize with other killifish. Lyretails tend to live for about three years—longer than most types of killifish.

Red-Striped Killie (Aphyosemion striatum)

• ORIGINS: Occurs in West Africa, restricted to pools and swamps in northern Gabon.
• SIZE: 2 in (5 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 64–72°F (18–22°C); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Nonaggressive.

Bright red horizontal stripes running along the body and a blue background help to distinguish male Red-Striped Killies. Females are a dull golden-brown shade, with rounded fins. Like other killifish, they eat small live foods, even freeze-dried items. The water should be slightly brackish, and their tank must be densely planted. It must also be kept covered, since these fish can jump. Java Moss (Vesicularia dubyana) is a good spawning medium.

Two-Striped Killie (Aphyosemion bivittatum)

• ORIGINS: West Africa, found in parts of Cameroon, Nigeria, and Togo.
• SIZE: 5 cm (2 in).
• DIET: Live foods and prepared diets.
• WATER: Temperature 22–24° C (72–75° F); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Peaceful.

The color of these killifish is highly variable, but in all cases males have more elaborate fins than females. The upper stripe on the fish’s body is more prominent than the lower, which runs along the underparts. As in other related aphyosemions, spawning is a lengthy process that takes place over the course of several days amid aquatic plants. For breeding purposes, several males should be housed with a single female. The eggs start to hatch after a period of three weeks.

Twin-Banded Killifish (Aphyosemion bitaeniatum)

• ORIGINS: West Africa, occurring in coastal parts of Nigeria, Benin, and Togo.
• SIZE: 2 in (5 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 72–75°F (22–24°C); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Males can be quarrelsome.

With their tall dorsal fin, the males of this species are exceptionally eye-catching. Their coloration is variable, although red may dominate, and there are usually two darker stripes down the sides of the body. Females are a dull brown, with less elaborate fins. Male Twin-Banded Killifish will fight, so they should be kept apart. House a single male with two females for spawning, which usually occurs among plants.

Clausen’s Steel-Blue Killie (Fundulopanchax gardneri)

• ORIGINS: West Africa, recorded in parts of Nigeria and western Cameroon.
• SIZE: 3 in (7.5 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 72–79°F (22–26°C); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Males are quarrelsome.

Brilliant blue coloration and a variable red-spotted patterning along the body identify the male of this species, seen below. The female Clausen’s Steel-Blue Killie has brown dots on its flanks and a duller coloration on the fins.This species does not require brackish water. Spawning in the aquarium occurs on fine-leaved plants or on a spawning mop. If the tank is left full of water, the fry will hatch after two weeks.

Blue Gularis (Fundulopanchax sjostedti)

• ORIGINS: West Africa, found in shallow waters in Ghana, Cameroon, and Nigeria.
• SIZE: 5 in (13 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 73–79°F (23–26°C); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Relatively aggressive.

The color on the flanks of the Blue Gularis is variable—yellowish in some individuals, as seen below, and greenish-blue in others. Keep just one male in the company of several females, and make sure the tank has a peat base, since these killifish are substrate-spawners. Remove the adults after spawning, and carefully drain the tank before removing the egg-laden peat and partially drying it. Refill the tank after laying a new peat base.

Walker’s Aphyosemion (Fundulopanchax walkeri)

• ORIGINS: West Africa, found in southern Ghana and southeastern Ivory Coast.
• SIZE: 2 in (5 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 68–73°F (20–23°C); soft (50–100 mg/l) and acidic (pH 6.0–6.5).
• TEMPERAMENT: Aggressive and active

Stunning bluish coloration on the flanks, red spots on the sides of the body, and yellowish fins are the key features of these fish. They spawn either among plants or on a peat base. Peat with eggs buried in it should be removed and stored in a warm place in a plastic bag so that it partially dries but does not become powdery. After about six weeks, put the peat back into the tank. The eggs will hatch quite rapidly, and the fry can be reared on brine shrimp

ISOLATION AND DIVERSITY

Some killifish, notably members of the Nothobranchius and Cynolebias genera, and a few Aphyosemion species, are known as “annual killifish,” because they die in the dry season when the temporary shallow pools in which they live evaporate. Others, including Lyretails, inhabit permanent bodies of water. Killifish populations tend to be isolated from one another, so these fish often display a wide range of color morphs. The diversity that exists within a single species can be seen by comparing the pair of Lyretails below with the example illustrated opposite.

Palmqvist’s Notho (Nothobranchius palmqvisti)

• ORIGINS: East Africa, found in coastal regions of Kenya and Tanzania.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 64–68°F (18–20°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Aggressive.

Nothobranch killifish can be distinguished from Aphyosemions by their broader bodies. Palmqvist’s Notho is an annual killifish with a red caudal fin and a bluish body covered with a meshlike pattern of red lines. Females are smaller and duller in color than the males, which are quarrelsome by nature. The care of these fish is straightforward, although they often do better in slightly brackish water. When breeding Palmqvist’s and other nothos, place the fish in a relatively small aquarium; it should be only about half full of water and have a peat base. Offer the fish plenty of live foods, and allow the water to evaporate naturally. The falling water level should trigger spawning behavior, and the female will lay her eggs in the peat substrate.

LONG-LASTING EGGS

Life is a brief affair for annual killifish, because the adult fish die each year when their pools dry up. However, the population itself survives, thanks to the way in which the killifish spawn on the substrate as the water level falls. Drying mud encases the eggs (shown magnified below) and protects them until the rains return, perhaps as much as two years later, filling the pools and allowing the next generation of killifish to hatch. The young fish grow rapidly, feeding largely on insects, and may reach maturity in just six weeks.

Korthaus’ Notho (Nothobranchius korthausae)

• ORIGINS: East Africa, restricted to swamp areas of Mafia Island, Tanzania.
• SIZE: 2 1⁄2 in (6 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 73–79°F (23–26°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Aggressive.

There are several morphs of this killifish. The example above is one of two red-tailed forms; the other has a blue body. In brown morphs, the body lines are brown rather than red, and the caudal fin is brown and yellow. Males are always brighter than females. The dependence of notho killifish on seasonal pools of water in the wild means that the water chemistry in the tank is crucial for these fish. They can live for a couple of years in aquariums.

Gunther’s Nothobranch (Nothobranchius guentheri)

• ORIGINS: East Africa, from Mombasa, Kenya, to the Pangani River in Tanzania, and on the island of Zanzibar.
• SIZE: 2 in (5 cm).
• DIET: Small live foods.
• WATER: Temperature 73–79°F (23–26°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Aggressive.

Highly colorful, yet variable in appearance, these killifish should be kept in groups of several females and one male. They will spawn in peat but often die soon afterward. To hatch the eggs, dry the peat, rewet, and dry again before placing in a tank. Some eggs only hatch on a second contact with water; this strategy helps to protect wild populations from being wiped out if their pool dries up prematurely.

Banded Panchax (Epiplatys annulatus)

• ORIGINS: West Africa, in streams in parts of Sierra Leone, Nigeria, Liberia, and Guinea.
• SIZE: 1 3⁄4 in (4.5 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 73–79°F (23–26°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Relatively peaceful.

The distinctive patterning of Banded Panchax— four broad, dark bands separated by paler areas—allows them to be identified with ease. Males have more colorful fins than females and also possess blue irises. Banded Panchax should be kept in a well-planted tank, under subdued lighting. They tend to swim close to the surface and will spawn among the vegetation, or on a spawning mop. These killifish will not eat their eggs, which should hatch after eight days.

Six-Barred Panchax (Epiplatys sexfasciatus)

• ORIGINS: West Africa, where its distribution is restricted to Cameroon.
• SIZE: 4 1⁄4 in (11 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 73–82°F (23–28°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Relatively peaceful.

This killifish is named after the six vertical bands that encircle its body, although these bands tend to be fairly inconspicuous. There are several localized forms, but in all cases the males are larger and more colorful than the females, which have more rounded fins. A breeding group of a male and two or three females will spawn among vegetation such as Java Moss (Vesicularia dubyana), or on a spawning mop. The eggs hatch within two weeks, and the fry can be reared largely on brine shrimp.

Dwarf Panchax (Aplocheilus blockii)

• ORIGINS: Asia, occurring in southern India in the vicinity of Madras; may also occur on Sri Lanka.
• SIZE: 2 in (5 cm).
• DIET: Live foods and prepared diets.
• WATER: Temperature 73–79°F (23–26°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Peaceful.

The yellow markings on the bodies of these killifish, which are the smallest members of their genus, are more vibrant in the males. Dwarf Panchax are reasonably tolerant, both of their own kind and of other nonaggressive fish of a similar size. As with other plant-spawning killifish, the eggs should be removed from the plants in the breeding tank each day and hatched separately. The young Dwarf Panchax will require infusoria at first.

Day’s Green Panchax (Aplocheilus dayi)

• ORIGINS: Asia, occurring in southern India in the vicinity of Madras; may also occur in Sri Lanka.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 73–82°F (23–28°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Peaceful.

The flanks of Day’s Green Panchax are bluish and bear dark markings. Females have smaller, more rounded fins than males. These lively killifish, which can be kept with other fish of a similar size, tend to occupy the upper levels of the aquarium. A cover for the tank is vital to prevent them from leaping out. They spawn quite readily, and the eggs, which are clearly visible, take 12–14 days to hatch.

Blue Panchax (Aplocheilus panchax)

• ORIGINS: Asia, from southern India eastward through Thailand and the Malay Peninsula to parts of Indonesia.
• SIZE: 3 in (7.5 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 68–77°F (20–25°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Rather aggressive by nature.

The Blue Panchax is one of the most widely distributed killifish species, with a number of variants found throughout its extensive range. The greenish body has a blue color along each side that often highlights the outline of the scales. The fins of the male (the lower of the two fish shown here) are more colorful than those of the female (the upper fish). Blue Panchax will spawn quite readily among fine-leaved vegetation in a breeding tank. The eggs are laid in batches, which can be hatched in small containers filled with mature water. The young typically emerge 10–14 days later; the length of this period is partly influenced by the water temperature. Partial water changes are very important for the subsequent well-being of the fry as the young Blue Panchax grow in size.

UNUSUAL KILLIFISH

Killifish are seen less often in aquatic outlets than other groups of fish, simply because their reproductive cycle makes it unprofitable to farm them commercially in large numbers. Instead, killifish are most often available as eggs, which enthusiasts trade among themselves. For this reason, some odd varieties, with anomalous requirements, are sometimes seen. One example is the Blue Tanganyika Killifish (Lamprichthys tanganicanus). While most killifish live in temporary pools with relatively soft, acidic water, this species inhabits Lake Tanganyika, where the water is very hard and alkaline. The Blue Tanganyika is the largest of all the African killifish, with males reaching 51 ⁄2 in (13 cm) long. It lives in schools around the lake’s rocky shores.

Orange Panchax (Epiplatys fasciolatus)

• ORIGINS: West Africa, occurring in Liberia, Nigeria, and Sierra Leone.
• SIZE: 3 1⁄4 in (8 cm).
• DIET: Live foods and prepared foods.
• WATER: Temperature 73–82°F (23–28°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Relatively peaceful.

These killifish do not display any well-defined pattern of banding. Males have red and greenish speckling on their bodies, with some populations being more colorful than others. Females are a much duller shade of yellowish-brown, with a rounded rather than elongated caudal fin. These killifish require a well-planted aquarium and will spawn among vegetation, such as moss. Orange Panchax may be persuaded to take flake sprinkled on the surface.

Banded Pearlfish (Austrolebias adloffi)

• ORIGINS: South America, in the lowlands between southern Brazil and eastern Uruguay.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared foods.
• WATER: Temperature 68–75°F (20–24°C); hard (100–150 mg/l) and neutral (pH 7.0).
• TEMPERAMENT: Males aggressive to unresponsive females.

About 10 vertical dark bands run down the greenish-gray body of the male Banded Pearlfish. The male’s dorsal and anal fins are more pointed than those of the female, whose coloration is made up of dark blotches on a brown background. Less aggressive than some related pearlfish, this species may spawn almost continually, so a removable peat tray is useful. The eggs will hatch after being out of the water for eight weeks.

Entre Rios Pearlfish (Austrolebias alexandri)

• ORIGINS: South America, in southern Brazil, western Uruguay, and northeastern Argentina.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared foods.
• WATER: Temperature 68–75°F (20–24°C); hard (100–150 mg/l) and neutral (pH 7.0).
• TEMPERAMENT: Can be aggressive.

Males are more brightly colored than females, with a yellowish-green body color and vertical bars along the flanks. In females, the body is blotched with brown and black. A red-eyed, pink-bodied strain also exists, in which the males have darker pink barring on the body and pale spotted fins. Although these pearlfish prefer small live foods, they may also be persuaded to sample flaked foods quite readily

Black-Finned Pearlfish (Austrolebias nigripinnis)

• ORIGINS: South America, in Argentina and also in parts of southern Brazil and Uruguay.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared foods.
• WATER: Temperature 68–72°F (20–22°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Can be aggressive.

Mature males of this species are blackish with a variable pattern of iridescent greenish spots and a green band across the top of the dorsal fin. Females can be recognized by their light gray coloration. The base of the spawning tank needs a thick layer of peat for spawning purposes. Store the eggs in moist peat in a plastic bag. They can be returned to the water after two to three months and may remain viable for up to three years.

Fighting Gaucho (Cynopoecilus melanotaenia)

• ORIGINS: South America, occurring in both southeastern Brazil and northern Uruguay.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared foods.
• WATER: Temperature 64–75°F (18–24°C); soft (50–100 mg/l) and acidic (pH 6.5).
• TEMPERAMENT: Aggressive toward its own kind.

A white throat plus two yellow bands along each side of the body, separated by a darker stripe, are defining features of this pearlfish. The top of the body is brownish, with reddish-brown color on the fins. Females are less brightly colored. The quarrelsome nature of Fighting Gauchos means that their tank must be well planted and have many retreats; however, they can be housed safely with unrelated fish. Pairs spawn on a peat substrate. The resulting fry can be reared on brine shrimp.

Bokerman’s Cynolebias (Simpsonichthys bokermanni)

• ORIGINS: South America, restricted to pools close to Ilheus, Bahia, near the Brazilian coast.
• SIZE: 2 in (5 cm).
• DIET: Small live foods and prepared foods.
• WATER: Temperature 68–75°F (20–24°C); soft (50–100 mg/l) and acidic (pH 6.0).
• TEMPERAMENT: Can be aggressive.

The identifying characteristics of the Bokerman’s Cynolebias are its greenish-gold body and blue gill covers, with vertical blue lines behind. Pale blue speckling is also apparent on the fins of males. Females are duller, with a black spot on the flank. These fish spawn in the substrate. As with other species, the peat carrying the eggs must be stored in a plastic bag at room temperature for about two months, before being returned to the aquarium so that the eggs may hatch.

American Flagfish (Jordanella floridae)

• ORIGINS: Extends from Florida around the Gulf Coast and down to Mexico’s Yucatán Peninsula.
• SIZE: 2 1⁄2 in (6.5 cm).
• DIET: Small live foods and prepared diets.
• WATER: Temperature 66–77°F (19–25°C); hard (100–150 mg/l) and neutral (pH 7.0).
• TEMPERAMENT: Males are aggressive.

The deep yet narrow body of the American Flagfish is decorated with a combination of bluishgreen and reddish-orange speckles; vibrant red is displayed on the dorsal fin. The female of the species can be distinguished from the male by a blackish spot at the rear of the dorsal fin and her generally duller appearance. Inhabiting densely vegetated stretches of water in the wild, American Flagfish require similar surroundings in their aquarium; otherwise, they will prove to be nervous tank occupants. Vegetable matter is an important component of the diet of these fish, and they will browse readily on algae growing in the aquarium. Males will become quite aggressive as the time for spawning approaches. The female can produce up to 70 eggs, either scattering them among the vegetation or burying them in the substrate. The male will usually guard the eggs for a week or so until they hatch.