Nothobranchius furzeri JUBB, 1971

Last updated 13 October 2000

Figure 1: Cox [BKA] obtained a yellow tail N.furzeri from a hatch of N. sp. "MOZ 99/4". The yellow crescent is however wider than in the Ghona Re Zhou population. {Photo: R. Cox}

 

furzeri: (Latinised adjective) in honour of Mr. Richard E. Furzer of Rhodesia through whose efforts the fish was introduced into the hobby.

First Description

Dr. R. A. Jubb [Albany Museum, Grahamstown, South Africa] - 1971 "A new Nothobranchius (Pisces, Cyprinodontidae) from South-eastern Rhodesia" - Journal of the American Killifish Association (JAKA)- 8 (1): 12-19, 4 figs.

Terra Typica

South-eastern Zimbabwe [formerly known as Southern Rhodesia]; Sazale Pan [=pool] belonging to the upper Guluene river system [near the Zimbabwe-Mozambican border], in the Gona-Re-Zhou Game Reserve. This area was set aside in 1960's to protect the great herds of elephants that roam this northern extension of the Kruger National Park in South Africa. However, it was converted to a detention centre for anti-government activists during the 1970's and severe poaching in the post-independence period has forced the closure of the park indefinitely.

Figure 2: Type locality of N.furzeri in the Sazale pan - Ghona-Re-Zhou National Park

 

Holotype

The holotype, an adult male, has a total length of 53-mm and a standard length of 44-mm. Collected on January 12, 1969, by Dr. W. Warne of the Rhodesia Department of Agriculture, from a pan known as Sazale Pan, approximately 21 40'S, 31 45 E, in the Gona-Re-Zhou Game Reserve. The type and nine Paratypes are preserved at the Albany Museum, Grahamstown, South Africa under registry number: AMG/P 1239 and P 1240.

Meristic & morphometric data

According to Jubb (1971; 1975a:112), the species is described by one type specimen and nine Paratypes, PF 1240, all males from the same locality. The species characteristics as presented by Jubb in 1971 are:

Characteristic

Holotype

Paratypes [9]

Total length

53 mm

120-126 mm

Standard length

44 mm

25 - 44 mm

Body depth

29.5

28.2 - 31.0

Head length

32.9

30.8 - 36.0

Distance snout-origin dorsal fin

56.6

54.0 - 62.0

Distance snout-origin pectoral fin

34.2

32.2 - 36.0

Distance snout-origin pelvic fin

50.0

48.6 - 53.8

Distance snout-origin anal fin

59.0

59.0 - 67.6

Note: Standard Length (SL) in mm - Other values expressed as percentage of standard length.

Characteristic

Holotype

Paratypes [9]

Snout length

27.4

25.0 - 28.9

Eye diameter

20.6

20.0 - 22.2

Interorbital width

43.5

41.7 - 44.5

Note: Values expressed as percentage of head length (HL).

There are 28 to 30 scales in the longitudinal series (excluding the scales at the base of the caudal fin); lateral line pores absent. Scales around the body immediately in front of the pelvic fins 22 - 24.

According to Jubb (1971), the snout is short, flat and broad. The mouth is directed upwards, with a projecting lower jaw. The teeth on the premaxillary are conical and sharply pointed,, placed in 3 to 4 rows, with 12 to 18 large teeth in the anterior row. Those in posterior rows are smaller, numerous and scattered. The teeth arrangement on the dentary bone is similar to that on the premaxillary, but the posterior rows consist of coarse teeth with flattened crowns.

The dorsal fin has 14 to 15 (15 in Holotype), the anal fin 14 to 16 (14 in Holotype) fin rays. The origin of the dorsal fin lies over or slightly in front of the anal fin origin. Mature males have the tips of the anal and caudal rays extending beyond the fin membrane (Jubb , 1971). In specimens of the same size there is no appreciable difference in the size of the anal fins of males and females, but males have a higher dorsal fin.

Karyotype: n=19, 38 arms

Synonyms

N. species Furzer 1969
N.kirki sensu Jubb 1969
N. U-2 Ricco, 1971

The synonyms most probably also include the following recently imported red form from
Mozambique:
N. sp. MOZ 99/4; N. sp. MOZ 99/5 and N. sp. MOZ 99/6. The reason for this synonymy is that Richard Cox (pers. comm.) of the BKA found in the first half of 2000 a yellow tailed furzeri-type male amongst a hatch of the red MOZ 99/4 fish. One male was a typical red MOZ 99/4-form, the other male resembled the yellow Ghona Re Zhou-form, although with a deeper red body and a wider yellow crescent in the tail (Figure 1 & Figure 8). Cox was assured that both populations could not have mixed (cover glasses and generally no jumping behaviour is observed in Notho's). The main difference between the red MOZ-forms and the yellow Gona-Re-Zhou-population is the presence of a red semicircular pattern in the caudal fin and the absence of a black marginal band in the former, while the latter has a rather narrow yellow vertical band/bar and a black marginal band in the caudal fin.

Figure 3: Male of the red N.furzeri form from locality "MOZ 99/4". {Photo: St. Valdesalici}.

 

For Wildekamp (1991) the species is closely related to N.kuhntae, which would represents the red phenotype. N.furzeri would then be considered as the blue phenotype. If this is verified then the name N.furzeri Jubb, 1971 should be changed into N.kuhntae Ahl, 1926 as the first description gets precedence over later ones and N.furzeri Jubb, 1971 would become a synonym of N.kuhntae Ahl, 1926.
However, with the recent import of the MOZ 99/4 -/5 and -/6 populations and with
Cox's recent discovery, it appears that these populations represent the red phenotype rather that N.kuhntae.

Dr. Jubb counts N.furzeri together with N.rachovii, N.kirki and N.kuhntae in a group of small Nothobranchius species (Foersch, 1975:112). This fish differs, both in coloration and size, from N.orthonotus (Peters), which can be found in similar rivers and temporary waters of Mozambique.

N.rubroreticulatus is defined as the type species of the subgenus Zononothobranchius, to which the following species most probably also belong: N.rachovii Ahl, 1926; N.kirki Jubb, 1969; N.furzeri Jubb, 1971; N.brieni Poll, 1938; N.polli Wildekamp, 1978; N.malaissei Wildekamp, 1978; N.symoensi Wildekamp, 1978; N.taeniopygus Hilgendorf, 1891; N.neumanni Hilgendorf, 1905; N.lourensi Wildekamp, 1977 and N.korthausae Meinken, 1973 (Radda, 1981:4).

Size

Aquarium males reach 55 to 60-mm, females reach up to 40 to 45-mm total length. The largest specimen collected to date has a total length of 5.3 cm [2.1 in] (Bell Cross, 1976). Our own experience indicates that when kept at lower temperature [22C] aquarium raised male specimens reached 65 cm total length in only 3 months and developed a humpback profile in the head-back region. Females raised in similar conditions reached 55 cm total length.

Code

FUR

Distribution & Habitat

According to Jubb (1971; 1975a:111), "in the south-east of Rhodesia the boundary with Mozambique straddles a low-graded watershed between the Nuanetsi (= Mwenezi) River, a tributary of the Limpopo, and the Lundi (= Rundi = runde), a tributary of the Sabi or Save Rivers. On the Rhodesian side of the boundary and wedged between these two large rivers is the Gona-Re-zhou Game Reserve with an area of some 2,000 square miles".

Figure 4: Administrative map of Zimbabwe
[Source FAO].

 

The species is found, as opposed to most coastal Nothobranchius species, at an altitude of some 300 to 600-m above sea level [1,000 to 2,000 feet] above sea level. According to Jubb (1971, 1975a:111), "on the watershed there are numerous water pans, which, during a good rainy season, drain south-east into the headwater tributaries of the Guluene and Chefu Rivers, which empty into the Chingovo River in Mozambique. The Chivongo then become a series of swamps, pans and small inland lakes indicating a drainage system, which, in earlier pluvial periods, must have drained into the Limpopo River. Although the mean rainfall is in the order of 16 inches, falls are extremely variable and erratic".

Figure 5: Meteorological profile of Zimbabwe
[Source FAO-CLIM]

 

According to Jubb (1971), "heavy rains in the summer are associated with occasional Indian Ocean cyclones, which sweep down the Mozambique coast but in lean years barely 10 inches are recorded in this area. As little precipitation of consequence occurs during the months April to September, water in the Gona-Re-Zhou pans is definitely seasonal, some of the pans being dry for four to five months of the year, and some remaining dry for a whole season".

Figure 6: Main crop zones of Zimbabwe.
[Source FAO]

Figure 7: Occurrence of N.furzeri in Southern Africa.

 

Average summer precipitation in the area is about 400 mm, but during drier years (El Niño effect) only half as much may be available. The rainy season, between October and January, also corresponds to the time of higher temperatures (30-35C or 86-98F). Between April and September, the shallow bodies of water progressively dry up. Jubb (1971) claimed that these waters were very rich in organic material as wildlife, including elephants, from the reserve came to these pools to drink. Water characteristics at the Sazale collection locality were recorded as pH 6.6 to 8.0 and hardness from 4-5 DH, although, in the original description Jubb (1971) mentioned that no data on the quality of the water were available.

Dr. Warne discovered N.furzeri, living together with N.orthonotus, on 12 January 1969 in an as Sazale known inner water, on 2140'S-3145'E., which, together with many other temporary waters, gives a peculiar character to this part of the Guluene drainage system.

It appears that the area is subject to tsetse fly infestation, which carry the sleeping sickness parasites and that it was used, during the struggle for liberation, as guerrilla basis. Because of this and the consequent depletion over the years of its wildlife due to poaching, the area still remains isolated. Rather striking is the fact that in vernacular language Gona-Re-Zhou means "elephant tusk". Other than very dedicated nature lovers and research personnel studying wildlife and tsetse fly control, hardly anybody has re-visited the area.

Bowmaker et al. (1978) mention the occurrence of N.furzeri in the Sabi and Lundi rivers drainage systems.

Figure 8: Occurrence of N.furzeri in Zimbabwe.

 

During end of March 1999, Trevor Wood, Johan Ippel, Pieter Kearney, Jan du Plooy and Peter Riley travelled to Mozambique and collected red forms of a furzeri-related "species" in the lower Limpopo drainage system. The location codes are MOZ 99/4, /5 and /6.

History

According to Jubb (1971), N.furzeri was collected by Mr. R. E. Furzer (Furzer, 1969) and Dr. W. Warne in March 1968, together with mature specimens of N.orthonotus Peters from one of the pans known as Sazale, which, with many others, forms part of the Guluene River drainage system. In this pool they also found the lungfish, Protopterus annectens.

In December 1968, J. V. Ludbrook from the Department of National Parks and Wildlife Management, Southern Rhodesia (now Zimbabwe), re-collected some more of the new Nothobranchius in a pool adjacent to Sazale. Some preserved specimens and colour photographs of adult males were sent to Jubb at the Albany Museum, Grahamstown, South Africa for identification.

 

In 1969, Jubb (erroneously) identified the new Nothobranchius species as N.kirki and called attention to the fact that colours of mature fertile males were of great significance in the determination of Nothobranchius species, because these fishes showed little, if any, morphological differences. The coloration of this Nothobranchius species from Gona-Re-Zhou National Park was unknown to Dr. Jubb and he sent colour photographs to hobbyists in England [British Killifish Association] and to the United States to Dr. R. J. Goldstein [Department of Biology, Emory University, Atlanta] for examination and comments by Nothobranchius enthusiasts. According to Jubb (1971), "Dr. Goldstein showed his slides to members attending the annual meeting of the American Killifish Association held in San Francisco early September 1969. Nobody had ever seen this fish alive nor seen a description in literature. Subsequently Mr. Robert Parle of California managed to obtain live specimens of this Nothobranchius from Rhodesia through the efforts of Richard Furzer. In collaboration with Mr. Joe Ricco, Parle succeeded in obtaining viable eggs from some of these fishes and specimens were hatched and tank-reared in America. Some of Parle's material was preserved and forwarded by Dr. Goldstein to the Albany Museum, Grahamstown, for study purposes". In 1971, in recognition of Furzer's efforts, Jubb described the species as N.furzeri.

W. Foersch was the first to introduce the species in Europe (Germany) from the U.S. in the summer of 1973 when he received 24 eggs from Rosario LaCorte of the American Killifish Association (Elisabeth near New York).

Description

In his original description Jubb (1971) mentions that the external characteristics of the species do not differ significantly from those of any other Nothobranchius of East Africa, but the colour pattern of mature males, as in all species of this genus, is constant but distinct from that of the then known species. Jubb (1971) gave following colour description: "The scale centres are iridescent turquoise edged with crimson which forms a reticular pattern when full breeding colours have developed. Pupil of eye bordered with gold, iris golden but pigmented with small dots; a dark vertical stripe passing through the pupil and iris. Pectoral fins pale orange edged with pale blue. Pelvic fins with pale blue membrane and brick red markings. Anal fin membrane pale blue heavily mottled brick red, the branched rays of the lower half being bright red and extending into the pale blue edging. The caudal fin base has a pale blue or pale grey membrane with liver-coloured markings between rays; the posterior portion of the caudal with a distinct pale yellow-orange band followed by a black band, the whole of the caudal fin being edge with black. The dorsal fin has a pale blue-grey membrane heavily mottled with liver-coloured markings, the rays being pigmented with black. The top edge of the dorsal in is pale blue. The ventral portion of the gill cover is jet black. Specimens preserved in formalin lose their turquoise and red colours but the markings on the fins and fin rays show up either as heavily pigmented dark grey or black areas" (Jubb, 1971).

Male specimens possess light blue-green to turquoise blue scales edged with carmine red, producing a net-like pattern. Gill covers are whitish on the upper part, going over into yellow in the lower portion, with black bordering. The eyes are iridescent gold with a dark, vertical transversal stripe, which extends over about 1/3 of the eye. Pectoral fins are light orange to yellow with a blue border. Ventral fins are yellowish-orange and spotted with carmine-red dots over a light blue base coloration. The anal fin has numerous red dots, some of which flow together. The red is more intense and forms bands in the distal and anterior parts of the anal fin with a similar base colour as the ventral fins. The dorsal fin is somewhat deeper blue sprinkled with small brown-red spots over the base, transforming into stripes from about 1/3rd of the height. The border is blue. Caudal fin is flamed over a blue underground with liver-brown stripes, ending in a vivid yellow band, to which follows a black band as tail ending.

Females possess a regular light grey-brown body coloration which can be at times light appear to be iridescent bluish. The scales are delicately edged in red. All fins are light olive, without any pattern, however, in appropriate lighting; one could discover a light bleu shining over them. The gill covers display a light golden shine. The caudal fin has also the shape of a spade as in males. Jubb (1971) added, "females have the same overall turquoise sheen to the scales which are outlined with pale brick red pigment, but the fins are un-pigmented with very pale blue or olive membrane. The base of the gill cover is golden".

Maintenance & Breeding

The very exiting coloration pattern of N.furzeri and its liveliness make it a very attractive species, possibly one of the most desired species in the genus. However, it has proven to have never become very popular because it has rarely been advertised or made available through the normal acquisition channels. In addition, it has a rather long incubation time, a relatively fragile composition and a short life span.

Two strains are known to the hobby: one with a very prolonged incubation time, very fast growing fry and very productive adults but after about 1 to 1 1/2 month they are struck with sudden death. The second strain has an incubation time of about 3 months and over, it has normally growing fry and the adults also live normally, dying of old age. There is no difference in colour or pattern between both strains.

Foersch (1975a:112) reported on the introduction of the species in Europe: "On 1 August 1973 I received a small glass tube with a few cubic centimetres water and 24 eggs in it. The water was murky as one fingerling had hatched and died during transport. One egg was clear and transparent, in the other 23 eggs one could recognise the ready developed embryos. I transferred the eggs for 3 days in clean water containing some antibiotic [Oxytetracyclin], followed by a one-day stay in water with some Trypaflavin. Considering that water incubated Nothobranchius eggs mostly produced belly-sliders, I wanted to give to these 23 remaining eggs a quick dry period. I then transferred them carefully onto a one-finger thick peat moss bed in a small glass recipient. After a few hours, one fingerling hatched. Whatever the water level, it remained a belly-slider. I then poured the water off and retained the rest in the glass recipient. The slightly humid peat moss containing the remaining eggs was kept in the glass container with closing lid at a temperature of 25C."

"When on 17 Aug. 73 I poured some water onto the peat moss six fingerlings hatched. Two of them could not swim and were resting on the bottom, the other four managed to swim freely some hours later. When emptying the water again out of the glass container I observed that all the other eggs in the peat moss had died. The four fry developed into two pairs. However, one of the males had a large gill-cover defect and one female had a deformed caudal pedicel. She could only swim head-down and only reached half-size. I was thus left with only one healthy pair. In only 3 weeks, the male developed darker drawings in the vertical fins and the light vertical tripe in the caudal fin became also visible. After 4.5 to 5.5 weeks they had coloured out [at 22-23C]" (Foersch, 1975a:112).

Figure 9: yellow tail N.furzeri obtained by Cox from N. sp. "MOZ 99/4". {Photo: R. Cox}

 

"After 5 weeks both males reached 4.5 cm in length - the largest male finally reached a length of 5.6 cm, the healthy female 4.8 cm. 30 days after hatching, the males started to drive the females and I could observe the first egg on the bottom on the glass spawning container. Thereafter I separated the sexes, fed abundantly the females and brought them again together every two to three days for a period of one to 2 hours only. Spawning follows the standard Nothobranchius procedures. The bottom of the tank was covered with a 1-cm thick layer of fine peat moss from which I could extract the eggs for control. The male drives only during short periods following which only a limited number of eggs are laid. When I collected these every other day, about 2/3 of them had died. The healthy eggs were stored away in peat moss. A small portion of the eggs was maintained for control at 23C in flat dish (in water) and I had to observe that many of these were already fully developed after only 3 weeks. After a short dry period in peat moss, I already had a new generation of young and healthy fish, which provided me with new eggs 6 weeks later, although this rapid water incubation of Nothobranchius eggs cannot be considered as the rule. Under ideal circumstances one could thus raise five generation in one year cycle" (Foersch, 1975a:113).

"The malformed pair died rather rapidly. The healthy pair reached an age of 4 and 1/2 month. After only 3 months, the male started to show sign of aging. He developed a humpback, was spending most of the time head-down at the water surface, and his body colours became increasingly faint. A couple of days before his dead he had driving, although very shortly, once again the female in the spawning tank and had displayed his most beautiful colour pattern" (Foersch, 1975a:113).

"I maintained the eggs in the peat moss at a temperature of 21C and I poured water over the eggs at different times. From the (low) number of hatched fry I noticed that still many eggs did not show any sings of development. After 4 and 1/2 months, I did not obtain any fry anymore. All the remaining eggs were still clear and transparent. After 5 to 5 1/2 months 5 to 10% of the eggs hatched. The remaining eggs did not show any sign of development. After 6 1/2 to 8 months many fingerlings hatched; clear eggs accounted for 10 to 40%. From such eggs I managed to obtain healthy fry after 10 1/2 months " (Foersch, 1975a:113-114).

"The embryological development is probably faster at higher temperatures. From the 76 eggs stored on peat moss at 21C, 5 fingerlings hatched after 5-1/2 month incubation, 53 eggs were still transparent. These remaining 53 eggs were stored at 26C on slightly humid peat moss. Only 2 weeks later, 43 fry hatched after wetting this humid peat, all the other eggs had died" (Foersch, 1975a:114).

Well documented is also the rather aggressive nature of males towards females and other males (Lühring, 1993), far more than in all other known Nothobranchius species. If one should attempt to breed with only one pair, one can bring them together for spawning for only a few hours a day. Females will only survive longer confrontation periods if, and only if and when, sufficient hiding places (plant cover) are being provided for in the tank and/or if the tank is large enough. One of the N.furzeri strains does not at all display this degree of aggressiveness. A positive point is that the fish likes middle hard water and an optimal maintenance temperature of between 22 and 26C [72-79F].

Considering that the period over which N.furzeri lays eggs is rather short, one will have to breed with several pairs together over a longer period [ continuous breeding set-up in large tanks] in order to ensure that enough eggs can be collected. This will also ensure that, after a while, adult fish can be kept alive the whole year round just as is being done with N.rachovii.

For breeding, it is being advised to utilise a small group of females for each single male. A dense plant cover and/or 2-3 drifting or half-sunken peat-fibre mops are also required to provide for sufficient hiding opportunities for the females and also to allow them to come to rest. Eggs are laid on peat moss, after an active pursuit and guiding process. The peat moss containing the eggs is regularly removed [ every 1-2 week(s) - at shorter notice if one wants to collect more un-fungussed eggs] , gently pressed until a light wet tobacco consistency is obtained and placed into a sealed and labelled plastic bag for an incubation period of between 3 to 5 1/2 to 6 months.

Lühring (1993) had an initial incubation period of only 6 weeks but with later spawns the period got progressively longer to 3-4 months. His obtained sex ratio is usually near to 50:50. He also recommends the use soft water during spawning in order to extend the liveliness of male semen and to increase the reproductive success.

At the time of first wetting, it can happen that no fry hatches at all. In such a case, the peat moss containing the un-hatched eggs is re-dried, stored again into the plastic bag and kept "humid-dry" for another additional month. It can also happen that the fry needs to be assisted in hatching from the eggshells [blowing CO2 into the hatch water or adding some Artemia-nauplii].

At hatching time, the fry is relatively large and can take immediately newly/freshly hatched Artemia-nauplii. Their growth is very rapid, possibly the fastest observed growth rate amongst all known killifishes. After about 4 weeks, sexes can be distinguished and after another week, they reach sexual maturity, this with a strong feeding program and with regular partial water changes. The addition of snails to remove uneaten food rests and of some water-lice (Daphnia spp.) to keep the infusoria under control is being advised during the development stages of the fry.

Water hardness is of lesser importance [1- 10DH] for an optimal maintenance. It is however recommended by some hobbyists to utilise clean, soft and slightly acidic water. This fish is preferably being kept in not too small tanks; recommended are 50-60 cm long tanks. A crucial aspect in the biology of N.furzeri remains the maintenance temperature, which should not be allowed to descend below 25C [72F] as otherwise the fish suffers and after only 2 days the first deaths will appear. As growth rate is very rapid and the fish consumes plenty of food, regular partial water changes are inevitable. Water pollution should be avoided at all costs and water temperature should be kept between 25 and 26C [72-79F]. Addition of salt [1 teaspoon per 5-litre water] is also recommended as a preventive measure against Oödinium (velvet).

Males' display quite some territorial behaviour and combat all their relatives without harming them, provided escape routes are on offer (large tanks). When not breeding, males are best kept separated as otherwise their brutality may kill inferior sex relatives. Their behaviour is unpredictable. A male may swim very quietly next to a female and suddenly storm onto her, in a hefty and impulsive lover's mood. At times, love affairs can be seriously rough as males bump heavily with their snout into the female's sides. Therefore, the availability of sufficient hiding places is an absolute necessity with this species [mops, Java-moss, floating plants with roots, peat-fibre mops, etc.].

Callewaert (1977) uses as breeding set-up, 1 male and several females in a small especially but simply set-up tank, filled with water of 1 to 5DH; pH 6,8 to 7,2 [both give results]; temperature 28C [82F]. In order to increase the egg production, he advises to breed with several trios in somewhat larger tanks [50l x 25h x 30d]. On the bottom of the tank he places a 20x12x15 cm plastic container, of which the coverlid has been perforated with a 50-mm diameter hole. The bottom of the container is covered with a 3-cm thick layer of properly boiled and rinsed peat moss, which serves as spawning substrate. The advantage of such a large spawning-box is preventing peat and eggs from being infested by mosquito larvae and other food residues.

After 3-5 days spawning, Callewaert (1977) separates the sexes for one week and brings them back together in a new spawning tank for a new 3-days spawning period. After having removed the breeders, the eggs are left for some 10 additional days in the same tank. Only then the peat moss containing the eggs is poured into a fine net, very gently pressed and left to dry-out a little further in an open plastic box which, in turn, is placed into a larger insulated foam box. Now the peat moss-cum-eggs is left to dry for 6-weeks at a constant temperature of 20-22C [68-72F]. After 6-weeks, the peat moss will still feel rather humid. Now, it is left to dry out further to reach the tobacco consistency by spreading it over news- or kitchen-roll-paper. Then, the eggs are left, in a sealed and labelled plastic bag, for at least 5 months in a dark place. After these 5 months [the incubation period can also require up to 9 months], the peat is wetted with 20C [68F] soft water. If the young hatch, they are moved to another tank containing water of the same composition. There the temperature is being progressively raised to reach 26C [79F]. If this is not done, one can count, after only 10 days, on an 80 to 90% mortality rate. The young, which at hatching time are rather large, appear at first wrongly built. When their belly has been filled a couple of times with Artemia-nauplii, they take back the normal fry appearance.

According to Callewaert (1977), N.furzeri is less prone to velvet attacks, and at hatching time there is usually a low percentage of belly-sliders; however, if the temperature is kept too low, the opposite situation prevails.

According to Van Es (1993), in case the humid peat moss-cum-eggs is being incubated at 27C [81F], one can go two ways:

According to Luehring (1975), it is difficult to determine the exact incubation time for the N.furzeri eggs. Also, one has to be aware that the peat moss containing eggs should never be allowed to completely dry-out but should be kept wet and humid all the time [ somewhat more wet than the well-known tobacco consistency] . Luehring obtained bad results with incubations in which the peat moss got too dry. The eggs seem to be in need of water in order to develop further. According to the same author, one will have to utilise soft water during the spawning process, as otherwise male reproductive cells do not remain viable for long enough.

When raising the fry, water hardness can be increased progressively with each partial water change, with the addition of 1 teaspoon of normal table salt per 10-litre water. The feeding operations must be frequent and plenty as the fish grows fast and lives fast. A regular water change is also necessary.

N.furzeri possesses however two negative sides: the first being that the species is very vulnerable to velvet (Oödinium) and the second that it is one of the shortest lived species. Mortalities caused by ageing can appear after only 3 months and some can survive up to 6 months. The average life expectancy is between 4 and 5 months.

Bowden (1995) found a constantly larger proportion of young furzeri's with shortened and/or malformed gill cover and mouth. This seems to represent classical signs of a degenerative inbreeding process. One of the solutions is the exchange of eggs/breeders amongst hobbyists before the species get any chance to disappear from the hobby.

As opposed to previous authors, B. Holler (1978) claims that N.furzeri is a rather simple species to breed and to maintain. For the maintenance, a tank of 20 litres and upward is sufficient. If individuals are being kept separated, they will not display their beautiful colours. The water plays only a secondary role, although it should not be acid and the temperature should be maintained around 25C [74F.], higher temperatures are however well supported, but not for longer periods. If kept at lower temperatures than in their natural waters, which can reach 30C [86F], the fish will easily live for up to one year without loosing their colours. They take any type of live food. Breeding is, like for most other Nothobranchius species, not difficult. Best is to use a special tank with a trio for the reproduction, to cover the bottom with a 10-mm thick, well cocked and properly rinsed, peat moss layer. The breeding period should however be short; otherwise one will have to ensure that enough hiding facilities are available to the females. The peat moss containing the eggs is taken out of the tank, gently pressed in the hand and left for one to 2 days to dry out a little further, until the well-known tobacco consistency is reached. The development of the eggs lasts between 2 and 10 months, in function of the incubation temperature. Hatching happens in water, which had been standing a while, with a temperature of 18C [64F]. The fry hatches some hours later and can immediately eat freshly hatched Artemia-nauplii. Growth is rapid and after 3 weeks one can distinguish the sexes, three weeks later they are sexually mature. For reproductive purposes, it is advised not to use the fish before they reach 2 months of age.

Bibliography

  1. Bowmaker, A. P.; P. B. N. Jackson, R. A. Jubb - 1978 - Freshwater fishes In "Biogeography and Ecology of Southern Africa" Ed. M.J.A. Werger, Imk Public., 2 vol. 1439 pages 189 figs, 2 tabs.
  2. Bowden, E. (1995) - Fish House Notes 1995, Part One. - B.K.A.Killi News N 356, May 1995: 72-75.
  3. Bell Cross, G. (1976) - The fishes of Rhodesia - Salisbury; 262pp: 197-198; 47 plates
  4. Callewaert, T. (1977) - Nothobranchius furzeri Jubb, 1971 - B.K.V. - Killi Kontakt; jrg. 5 nr. 2 maart-april 1977:43-46.
  5. Foersch, W. (1975a): "Eine neuer Prachtgrundkärpfling: Nothobranchius furzeri Jubb 1971" - DATZ, 28(4):111-115, 8 figs.
  6. Foersch, W. (1975b): "Nothobranchius furzeri (Jubb 1971)" - Journal American Killifish Association; Vol.8; N.11; November 1975: 315-321; 7 photo's.
  7. Furzer, R. E. (1969) - "A Rhodesian Hobbyist Reports" - Trop. Fish. Hobbyist, 17 (6): 24-27, 1 fig.
  8. Holler, B. (1978) - Nothobranchius furzeri; DATZ 31(12):397-398, 1 fig.
  9. Jubb, R. A. (1971) - A new Nothobranchius (Pisces, Cyprinodontidae) from Southeastern Rhodesia - Journal of the American Killifish Association (JAKA)- 8 (1): 12-19, 4 figs.
  10. Luehring, D. (1975) - "My Experiences with Nothobranchius furzeri" - J.Am.Killifish Assoc., Vol.8; N 11; November 1975:322-324, 1 fig.
  11. Lühring, D. (1993) - "My Experiences with Nothobranchius furzeri" - J.Am.Killifish Assoc., 26(1): 21-23.
  12. Radda, A. C. (1981): "Synopsis der Gattung Nothobranchius Peters"; Vereinsberichte Informationen Programme; 7(5): 3-7, 10 figs.
  13. Skelton, P. H.; Stuart, P. (1987) - "" - Ann. Cape Prov. Mus. (Nat. Hist.), Vol. 16, Part 8: 179-189.
  14. Van Es, H. (1993) - Nothobranchius furzeri - BKA-Killi News N 336: 141-143 - September 1993.
  15. Wildekamp, R. H. (1991) - "Nothobranchius furzeri Jubb, 1971" - K.F.N. Killi-Bericht; Killi Nieuws 21 jrg.; N 2 April 1991; 2 figs.