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OTHERS
KNIFEFISH
Knifefish belong to two orders:
: Gymnotiformes and Osteoglossiforms. Members of these orders are generally large with strong lateral compression and elongated bodies. A long fin, often formed by the junction of the anal and caudal fin, is common to Knifefish.
GYMNOTIDAE FAMILY
The order Gymnotiformes includes the family Gymnotidae, which is made up of six sub-families;Apteronotinae, Electrophorinae, Gymnotinae, Hypopominae, Rhamphichthyinae, and Sternopyginae. Three of these sub-families are includedin the book, Apteronotinae, Gymnotinae, and Rhamphichthyinae.
APTERONOTINAE SUB-FAMILY
The Apteronotinae or Speckled Knifefish family inhabits freshwater habitats of South America. Thesefish are laterally compressed with a long anal fin which is moved in an undulating motion. The caudal fin is very small and slender. These fish possess a weak electrical organ at the caudal penuncle used for locating food in water with poor visibility. The anus is located on the underside of the head.
Ghost Knife Fish, Black Ghost Knife Fish, Speckled Knife Fish
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Apteronotus albifrons
SYN
:
Sternarchus albifrons; Sternarchusmaximiliani
PD
: An elongated, laterally compressed species with a log anal fin. The caudal penuncle is also long, and the caudal fin is very small. The entire fish is black, save for a white band at the caudal penuncle and another at the base of the caudal fin.
SIZE
: To 19" (48 cm)
SS
: None
HAB
: South America; widespread throughout the Amazon and Paraguay river in Brazil, Ecuador,Guyana,Peru
S
: bottom, middle
TANK
: A tank measuring 40" (152 cm) with a capacity of 45-55 gallons (170-210 L) is sufficient for a medium-sized fish. A significantly larger tank is need for adult size specimen-those over12" (30 cm). Provide many hiding places among rocks, wood, pipes, and tubes. The tank should be dark, possibly with a cover of floating plants. The tank should have dense planting and a soft substrate.
WATER
: pH 6-7 (6.7); 4-12 dH (7); 75-82°F (24-28°C)
SB
: This timid species that is territorial and aggressive towards others of its own kind. This species can be kept with without problems with peaceful fish not large enough to swallow. Be sure to provide retreats. This species should not be kept in pairs, although several fish can be kept in a large tank.
SC
: Angelfish, Discus, Eartheaters, Acaras, Gouramis,
Leporinus
,
Anostomus,
catfish
FOOD
: Live;
Tubifex
, crustaceans, earthworms, insect larvae; chopped meat; tablets
SEX
: Unknown
B
: Unknown; although simulating the rainy season could serve to activate spawning.
BP
: 10. There are no reports of successful spawning in captivity.
R
:This species may rest lying on its side. Under favorable conditions, this fish can belong lived.
DC
: 7.This species is sensitive to water pollutants, changes in water conditions, and medications. The Black Ghost Knifefish requires a diet including live foods.
Brown Ghost Knifefish, Little-Scale Knife
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Sternachella schotti
SYN
: None
PD
:An elongated species with a long snout. The anal fin runs from anus on the underside of the head to the caudal penuncle. The caudal fin is very small. The coloring is brown black with a slenderwhite band at the base of the caudal fin.
SIZE
: To 8" (20 cm)
SS
:
Apteronotusleptorhynchus
HAB
: South America; widespread throughout the Amazon River Basin
S
: bottom
TANK
: A 40" (101 cm), 45-55 gallon (170-210 L) tank is sufficient. Follow suggestions for
A. albifrons.
WATER
: pH 5.8-7.5 (6.8), 3-14 dH (8), 73-81°F (23-27°C)
SB
: An interesting fish which is aggressive towards similar species, those of the sub-familyApteronotinae. Otherwise, this species can be combined with almost any other peaceful fish. Do not combine with swallow able fish.
SC
: Angelfish, Eartheaters, Acaras, catfish, Silver Dollars,
Leporinus, Anostomus,
Gouramis.
FOOD
: Live; insect larvae, worms,
Artemia
; tablets; chopped meat
SEX
: Unknown
B
: Unknown
BP
: 10. Has not been reported.
R
: This species frequently rests lying on its side.
DC
: 5. This hardy, robust species should have live foods included in its diet.
GYMNOTINAE SUB-FAMILY
The Gymnotidae or Knifefish family also inhabits the fresh waters of South America. These fish are similar in body shape to those of the sub-family Apteronotinae and also possess a weak electric organ.
Banded Knifefish
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Gymnotus carapo
SYN
:
Gymnotuscarapos, G. fasciatus
PD
: The front part of the body is cylindrical. The rear part is compressed and ends at a point. Their are no dorsal, ventral, or caudal fins. The anal fin, which is used to propel the fish backwards or forwards by an undulating motion is very long. It starts behind the pectoral fin and extends to the end of the body. The mouth is broad and somewhat upturned. Young individuals are yellow to flesh in color with a few wide, brown to gray vertical stripes. On older specimens, the stripes are more abundant and darker in color.
SIZE
: To 24" (61 cm)
SS
: Other
Gymnotus
species
HAB
: Widely distributed throughout Central and South America. Ranges from Guatemala south to the Riode la Plata.
S
: bottom, middle
TANK
: A tank of 40" (101 cm) with a capacity of 45-55 gallons (170-210 L) is sufficient for individual fish under 8" (20 cm) in length. Specimen over 15" (38 cm) require a tank of at least 60"(152 cm) with a capacity of 90-110 gallons (340-410 L). The tank should be well-planted with large sturdy plants. Provide many retreats among rocks, wood, pipes, and tubes. The lighting should be dark, perhaps diffused by a cover o floating plants.
WATER
: pH 6-7.5 (6.9); 4-18 dH (8); 73-82°F (22-28°C)
SB
: This species is aggressive towards others of its own kind, but peaceful towards non-swallowable tank mates with dissimilar body characteristics. Combine with medium to large sized fishes that will not nip fins.
SC
: Eartheaters, Pacu, Arowana,
Leporinus, Anostomus
, Acaras, Cichlasomines,Pimelodids, Doradids, Driftwood Cats, Loricarids.
FOOD
: Live; earthworms,
Tubifex
, insects, fish, crustaceans; chopped meat;tablets
SEX
: Unknown
B
: Unknown
BP
: 10.No spawnings in captivity have been reported.
R
: Nocturnal, but can be coaxed to come out to feed during the day, if lights are off or the tank is dark .Can take atmospheric oxygen by swallowing air at water surface. Possess a weak electrical organ whichallows it to find food in muddy or dark water.
DC
: 6. This large, hardy fish is peaceful towards different tank mates. Live foods should be included in its diet.
RHAMPHICHTHYINAE SUB-FAMILY
The Rhamphichthyinae or American Knifefish family inhabit fresh waters of South America. These fish are similar in body shape to those of Apteronotinae except those of Rhamphichthyinae lack a caudal fin and teeth. These fish have a weak electric organ at the caudal penuncle.
STERNOPYGINAE SUB-FAMILY
The Sternopyginae inhabit the fresh waters of South America.
Glass Knife Fish, Green Knife Fish
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Eigenmannia virescens
SYN
:
Cryptopshumboldtii, C. lienatus, C. virescens,Eigenmannia lineata, E. humboldtii, Sternarchus virescens, Sternopygus humboldtii, S. lineatus
PD
: An elongated fish that lacks a caudal fin. The body is transparent but light brown colored. Sometimes the flanks may have a green iridescence. The backbone can be seen through the body. Two fine, lateral stripes are present; on that runs along the base of the transparent anal fin,and the other located just above this stripe. The head is dark brown to pinkish beige.
SIZE
: Males to 18" (46 cm), females rarely exceed 11" (28 cm)
SS
: Other
Eigenmannia
species
S
: bottom, middle
HAB
: South America; underneath islands of floating meadows in flood plains in the Amazon basin
TANK
: A tank measuring 48" (122 cm) with a capacity of 55 gallons (209 L) is recommended. Plant the tank heavily and use a cover of floating plants to diffuse the lighting. Provide plenty of hiding places among rocks, wood, and pipes. This species prefers "old water."
WATER
: pH 6-7.5 (6.9); 4-15 dH (10); 73-82°F (23-28°C)
SB
: A peaceful Knifefish that, unusually, should be kept in groups. A social structure will be formed with a dominant fish and weaker members. Combine with peaceful species too large to swallow.
SC
: Loricarids, Armored Catfish, Doradids, larger tetras, dwarf Acaras, Angelfish, Headstanders
FOOD
: Live; small fish, snails, crustaceans, earthworms, mosquito larvae,
Tubifex
;tablets, acclimated individuals may accept flakes.
SEX
: Males are obviously larger and have a larger caudal penuncle.
B
: Stimulating the rainy season helps initiate spawning. Use soft water (2-4 dH). Spawning takes place in the early morning hours. Eggs are laid in small amounts during each pairing, which lasts from 3-6 hours. In all, 100-200 eggs are usually laid on roots of floating plants. Remove eggs and transfer them to rearing tank. Raise the fry on
Artemia
nauplii.
BP
: 9.Breeding is very difficult.
R
: During spawning, the Glass Knife Fish emits electrical signals. These electrical signals can be heard with the aid of an amplifier, a speaker, and two electrodes. These signals produce songs that are thought to helpfish to pair up.Use a good water conditioner. Sensitive to new water added during water changes. Prefer water that has been standing for a while.
DC
: 6. This nocturnal species requires a diet of live foods and is sensitive to changing water conditions.
NOTOPTERIDAE FAMILY
The Notopteridae or Featherback Family includes four genera;
Chitala, Notopterus, Papyrocranus
, and
Xenomystus
, and six species distributed throughout Southeast Asia and Africa. The fish of this family are similar in body shape to other Knifefish, except the anal and caudal fins are merged together to form a large fin.
Clown Knifefish, Featherback
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Chitala ornata
SYN
:
Notopterus chitala
PD
: This elongated fish is high-backed with a long fin formed by the connection of the anal and caudal fins. The body color is silver-gray with four to ten distinct, black ocelli on the rear part of the body. Each ocelli is surrounded by a white area. The fins are somewhat darker gray.
SIZE
: To 40" (101 cm) in nature; not usually more than 18" in captivity.
SS
: Resembles the African Knifefish (
Xenomystus nigri
) and the Asian Knifefish(
Notopterus notopterus
) when young.
HAB
: Southeast Asia; calm, overgrown backwaters of large rivers in Burma, India, Thailand
S
: bottom, middle
TANK
: 40" (100 cm) or 45-55 gallons (170-210 L) is sufficient for young individuals. When fish reach 12" (30 cm) they should be moved to an 60" (152 cm) or 90-110 gallon (340-410 L) tank. The tank should be dimly lit with a cover of floating plants. Provide hiding places with pipes, caves, wood,and rocks. Have densely planted areas, but leave large, open swimming areas.
WATER
: pH 5.5-7 (6.3), 2-10 dH (5), 75-82°F (24-28°C)
SB
: Small fish will be eaten, so combine with other large fish. The Clown Knifefish likes to form small,loose schools when young. Adults become more aggressive and territorial and should be kept singly.
SC
: Arowana, Bichir, Oscar, Cichlasomines, Pimelodids, Loricarids, Asian Catfish, GiantGourami
FOOD
: Live; fish,
Tubifex
, snails, crustaceans, earthworms; occasionally pellets and tablets.
SEX
: Unknown
B
: The pair will spawn in tanks with very soft water. The eggs are laid in floating plants and sometimes on hard surfaces. The male guards them, chasing off other fish and fanning the eggs. The eggs hatch after 6-7 days. Transfer the fry into a rearing tank. Start feeding with
Artemia
.
BP
: 8. The main problem encountered in trying to breed this fish is the large size that must be attained to reach sexual maturity.
R
: Nocturnal. This fish is most active at dusk and daybreak. This fish is consumed by people in its native lands. A variation, the "Royal Knife" is also available. This type has more ocelli markings.
DC
: 6.A fish peaceful towards different species whose diet should include live foods.
Asian Knifefish
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Notopterus notopterus
SYN
:
Gymnotusnotopterus
PD
: This elongated, laterally compressed fish has an arched back The body coloring is brown-violet to brown and the fins are lighter. The mouth is large, while the dorsal fin is small.
SIZE
: To 14" (35 cm)
SS
: African Knifefish (
Xenomystus nigri
)
HAB
: Widespread throughout Southeast Asia; Burma, India, Java, Malaysia, Sumatra, Thailand
S
: bottom, middle
TANK
: A tank measuring 40" (101 cm) or 45-55 gallons (170-210 L) is sufficient. Follow suggestions under
C. ornata
.
WATER
: pH 5.5-7 (6.5), 2-12 dH (6), 75-82 F (24-28 C)
SB
: The Asian Knifefish may be best kept in a species tank, although it can be combined with other medium to large fish. The Asian Knifefish is aggressive towards its own species. This nocturnal species is territorial.
SC
:
B.schwanenfeldi
, Asian Catfish, Loricarids, Pimelodids, Giant Gourami,Loaches, and peaceful cichlids
FOOD
: Live; fish,
Tubifex
, snails, crustaceans, earthworms; tablets
SEX
: Unknown
B
:Spawning takes place at night, with 150-200 eggs being dropped on the bottom and rocks. The male guards them, chasing off other fish and fanning the eggs. The eggs hatch after 2 weeks. Start feeding with
Artemia
.
BP
: 9.Breeding is fairly unusual
R
: This species is very similar to
Xenomystus nigri
. These two species can be distinguished by
X. nigri
's lack of a dorsal fin.
DC
: 6. This aggressive species requires well maintained water and a diet including live foods.
African Knifefish
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Xenomystus nigri
SYN
: None
PD
:This elongated, laterally compressed fish has an arched back The body coloring is brown-violet to brown and the fins are lighter. The mouth is large, while the dorsal fin is small.
SIZE
: To 12" (30 cm)
SS
: Asian Knifefish (
Notopterus notopterus
)
HAB
: Northern Africa; still and slow-moving water of the Nile basin in Zaire, Gabon, Niger,and Liberia.
S
: bottom, middle
TANK
: A tank measuring 40" (101 cm) or 45-55 gallons (170-210 L) is sufficient. Follow suggestions under
C. ornata
.
WATER
: pH 5.7-7.5 (6.8), 2-10 dH (6), 73-82°F (23-28°C)
SB
: When young, this species does best when kept in a small group. Older fish become aggressive and intolerantof other Knifefish.This species can be combined with other medium to large sized species. Be aware that
X. nigri
will eat small fish.
SC
: Haplochromines, Mormyrids, African Butterfly fish, African Tetras,
Synodontis,
West African Cichlids.
FOOD
: Live; fish, earthworms,
Tubifex
, snails, insects, insect larvae, crustaceans; chopped meat; tablets, needs a varied diet.
SEX
: The female has a more rounded body around spawning times.
B
: 150-200 eggs are laid at night in holes and crevices. The male guards the eggs, which hatch in 6-9 days. Transfer the fry into a rearing tank and start feeding with
Artemia
.
BP
: 9. Breeding is difficult and infrequent.
R
: Nocturnal. The African Knifefish emits chiming bell-like sounds when swallowing air at the water surface. This species has a swim-bladder which serves as a respiratory organ. This fish rests in an oblique position with its head down. The African Knifefish emits barking sounds during courtship. This long-lived fish adapts well to tanks, but is shy when first introduced.
DC
: 5. This species requires a diet that includes live foods.
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