After Johann Paul Arnold, German aquarist.

Boulenger G.A. 1908. (Fundulus arnoldi).

Description of two new Cyprinodont fishes from West Africa.

Annals & Magazine of Natural History (8) 2 (7): p 29-30.

Boulenger 1915 also gives other references-

• Boulenger. Ann & Mag.N.H. (8) 2 1908, p 29.
• Paul Arnold, Bl.Aq.Terr. 1908, p.585, plates, figure 1.
• Woch.Aq.Terr. 1911, p 602, figure.
• Träber, Bl.Aq.Terr. 1912, p 351, figure.

5.5cm (in original description)

• D = 15-16, A = 15-17, ll = 25-27 (Boulenger 1908)
• D = 12-13, A = 14-16, ll = 28-32 (Rachow 1928)
• D = 15-17, A = 15-18, ll = 24-29 (Scheel 1968)

n = 19, A = 31 (Scheel 1990)

Paludopanchax

• Fundulus arnoldi Boulenger 1908
• Fundulopanchax arnoldi Rachow 1928
• Nothobranchius (Fundulopanchax) arnoldi Ahl 1932
• Aphyosemion arnoldi Myers 1933

• Port Harcourt
• Sapele (Blue phenotype) (western Niger delta)
• Ughelli TR 01(near Warri)
• Warri (Yellow phenotype) (western Niger delta)
• Wokocha River (Yellow phenotype) (eastern Niger delta)
• NG MM 14 - Ughelli

CI 2011 CW - Commercial import into the USA.

Photo courtesy of Jeff Wasley

Ughelli - Collected near Warri & imported as a private shipment to Boston in the USA by Terceira & Rossi in December 2001. Around 300 fish were imported in this shipment. Tony commented to me how variable the males were & considered Alf's photo's a true sample of the variability received.
The photos below are all F1 fish from different parents which came out of the original Ughelli TR 01 batch.
Alf informed me that the F2 generation also show a great degree of variation.
In 2014 a shipment of Killies was imported to the USA from the Niger Delta area. This was coded NG MM 14 which stands for Nigeria -Macowiak & Mazzola 2014.

The original description is given as 'mouths of the Niger' which is most likely the Niger delta. In Boulenger 1915 types 1-4 originate from Warri. Types 5 & 6, from Sapelle. All types being presented by Arnold.

Mainly restricted to the Niger Delta & a little further to the northwest.

Slow moving streams & swampy areas of small rivers & brooks in coastal rainforest..

Similar to Fp.filamentosus but can be separated by the caudal peduncle which is much thinner. The caudal fin tends to fan out more in Fp.arnoldi. The general appearance of Fp.arnoldi is that of a more delicate fish.

The unpaired fins of arnoldi are generally clear whereas these fins in filamentosum are spotted.

Eggs seen under a microscope also show differences. Eggs of filamentosum are larger than arnoldi & have few 'hairs' whereas arnoldi are smaller & have a noticeable amount of 'hairs'.

See also Fp.filamentosus.

Originally collected by Groch, a German sailor from the Warri area in the western Niger Delta. Groch collected fish for Schroot of Hamburg. This shipment which arrived on the 5th of November 1905 contained 8 specimens of a new fish. Arnold bought one male & two females, the remainder were sold to Thumm who lost them all apparently. Arnold's stock also died in 1906 but 3 preserved specimens were sent to Boulenger who based his desciption on them.

According to Scheel (Aquarium Journal May 1963), the first imports of this sp. contained 2 different colour forms, red & blue. The red form was introduced first & he considered this to be the 'typical' form. The blue form was identified by Boulenger as 'gardneri' & was pictured by Dietrich in 'Wochenschrift in 1915. This showed a filamentosum like form. Arnold is reported to have supplied these fish which were reportedly collected from Calabar (Cross River drainage).

In 1906 another shipment containing 20 specimens arrived in Hamburg. Other shipments containing the species were also recorded in 1910 & 1911. After this their seems to be a gap until the next import in 1961. Other imports did arrive but these fish were considered to be Fp.filamentosum.

Boulenger gives the following collectors / locations in his 1915 Catalogue.

• 1-4 (Types). Collected at Warri by J.P.Arnold
• 5. As above but not used as a type.
• 6. Collected by J.P.Arnold at Sapelle.

In 1961 Ulf Hannerz collected Fp.arnoldi from the Wokocha River 12-13 miles from Port Harcourt in the direction of Oweri. These were returned to Stockholm but were difficult to keep alive & Hannerz gave Scheel the remaining stock. These were the first fish which were succesfully bred & raised in captivity. Scheel lost his stock in 1967.

This sp. was known to have been in the AKA 'some years' prior to 1963 as Franz Werneri from Detroit sent Scheel slides of a fish known as 'gardneri' which were now identifiable as filamentosum.

East German aquarists had the species from Nigeria around this time & managed to breed them. These were apparently identical with the Wokocha River population.

Imported by the BKA from the Sapele - Warri area to the west of the Niger Delta in December 1975. Also in this shipment were 2 pairs of Fp.deltaensis then called 'Deltafish' by John Parker.

Around 1980 a pair was known to have been brought into the UK which
originated from a commercial source in Germany. One generation was raised &
distributed in the UK & Holland but these proved to be sterile. It was
thought likely that the female belonged to a different species (possibly Fp. filamentosum) though this could not be confirmed.

Not a very productive sp. Eggs are laid in productive periods with resting periods following where no attempts are made to spawn. Peat is a good substrate for egg laying although coconut fibre & silver sand should work equally well although I have not tried these on this sp. Semi-dry incubation takes about 6-10 weeks. Fry are small. Some literature states they will take newly hatched brine shrimp as a first food but I would prefer infusoria for a couple of days or a smaller shrimp such as San Francisco. Growth can be rapid with sexual maturity reported at 2 months.

Water quality has been reported as important & should be soft & around 6.0 - 6.5 pH (rainwater is a good choice). Temperature 74-78'F.

Velvet is a big killer of fry & tanks should be kept very clean especially of uneaten brine shrimp. The fry are salt tolerant & the addition of a teaspoon to the gallon is a wise precaution.

J.P.Arnold wrote a breeding account in the Aquarium Journal of June 1949. He used a 5 gallon tank for the breeding pair planted with Vallisneria, added one part of sea water to nine parts of fresh water. The temperature was 75°F, no other measurements of pH etc were given in the article. The surface was covered with large water ferns. He didn't use any aeration. The side of the tank nearest a window was shaded with dark paper no higher than the water level (8"). The fish were fed a diet of mosquito larvae, chopped earthworms & Daphnia. In this setup growth was rapid & the female became roed up.
Following spawning (presumably over a day) the pair are taken out & the water level was reduced to 2" & shaded as he considered light to turn the eggs sterile. He noticed the first fry 3 weeks later. He considered that infusoria was already present in the tank but added more from a culture. After a few days they were started on newly hatched brine shrimp. Growth was observed to be slow at first but accelerated as soon as they could take Cyclops & Daphnia.
He mentioned at the end of this piece that egg hatching would be 'hastened' at a low temperature of 70°F.

Otto Böhm gave a breeding report in JAKA Vol.9 No.11, November 1976. He had a pair from the UK. Eggs from this pair were examined at 8 weeks of dry incubation & found to be fully developed. A further week was waited before putting the eggs into water with the result that 12 fry emerged. These were fed on newly hatched brine shrimp. They turned out to be 6 pairs. Otto recommended using 1 male to 2-3 females in a breeding setup.
Water changes were observed as being useful in general well being & a willingness to spawn. Peat used for spawning was best washed & boiled & should not be too acidic. Soft water up to DH 15 was found to work well. Eggs were observed to be non sticky. The peat was harvested every 2 weeks & dried on tissue paper. An incubation period of 8 weeks was found to be enough to bring them to full maturity.

Sterba's 'Freshwater Fishes of the World p 488 considers them very prolific laying 15-25 eggs daily in a spawning period of 4-6 weeks. Eggs in water take 35-40 days of incubation. It is also stated that eggs from the 'blue race' are larger than those of the 'yellow race'.

The AKA have been hatching the Ughelli population OK after 6 weeks of dry storage (from e-mail 7th Feb.2002).

1·0 - 1·1 mm (Scheel).

Egg of Ughelli TR 01 population.
Photo courtesy of Adam Rychlik

Fry & adults are susceptible to velvet. Scheel considered them susceptible to mycobacteria infection & recommended maintaining them in 'clean, hard alkaline water'.

In BKA auctions of 1988/89 they were fairly easy to find.

It is thought that Fundulosoma thierryi is derived from this species.