After Herr Riggenbach who first collected the species.

Ahl E. 1924. Fundulus riggenbachi

Neue afrikanische Zahnkarpfen aus dem zoologischen Museum Berlin.

Zoologischer Anzeiger 61 (3-4): 135-145: p 142-143.

Ahl used 4 fish in his description.

Males 7cm, females 5cm.

• D = 11-13, A = 11-13, ll = 26-28 (Ahl 1924)
• D = 12-14, A = 13-15, ll = 26-29 (Radda & Pürzl 1987)
• D = 13, A = 14, D/A = 4, ll = 28 (Huber in Killidata)

• n = 10-19, A = 34-38 (Scheel 1974)
• n = 10, A = 34 (Huber in Killidata).
• Variability from 2n = 20 to 2n = 38 (Agnèse 2006)

Chromaphyosemion

• Fundulus riggenbachi Ahl 1924
• Fundulus bivittatus (non Lönnberg 1895) Pellegrin 1929
• Aphyosemion riggenbachi Myers 1933
• Aphyosemion riggenbachi BIV-GI
• Aphyosemion riggenbachi BIV-YA
• Aphyosemion bivittatum riggenbachi Lazara 1979

Populations

• Bonépoupa 2
• Cellucam
• Dibamba (Nyam Tam)
• Dibeng
• Dibombe (An isolated population at the northern edge of distribution)
• Dibini
• Henda River - HLM 18/99
• Kondé
• Makemba-Souza
• Mandjap
• Ndokama 1
• Ndokama PK 12 & PK 15
• Ndokpo
• N'kapa (Discovered by Poliak & Chauche about 16 km west of the Wouri River) Amiet 1987 considered this location to be the western limit of the sp. distribution area although more work was needed in this direction)
• Nkokem
• Nkondjok (misspelt Nkondjock)
• NKWO - 97 / 1 (Possible corruption NKWO 78/1)
• Quelle (Yabassi)
• Ruisseau Séla
• Solé
• Somakak
• Song Makak
• Tibéti
• Vari North
• Yabassi
• ABC 05 / 18 - 13 km south of Edea-Yabassi crossroad
• ABC 05 / 19 - Nkouli-Ngnock
• C 89 / 18 - 20km north of Bonépoupa
• C 89 / 19 - 16km north of Bonépoupa
• C 89 / 23 Cellucam
• C 94 / 1
• CMG 23 / 5 - Ham
• HAH 98 - Bonepoupa
• HJRK 92 / 18 Ndokama
• HJRK 92 / 19 Ndokama
• KPI 89
• PK 12 Ndokama
• PK 15 Ndokama

Bonepupa HAH 98 - http://www15.brinkster.com/runo7/rig2.htm Nonn Pantivong's site.

Ndokama -

Nkapa -

Nkokem -

Somakak - http://www.nakashima.org/ga_riggen_so.htm Japan Gallery

Yabassi - David Astbury wrote a report on this population in BKA newsletter No. 182, October 1980. This population was collected in January 1979 in a narrow stream 24 km from the Douala - Edea crossroads in the direction of Yabasso (Yabassi ?). The fish were collected away from the banks under plants & overhanging vegetation. Water temperature 21° C, pH 6·5, electrical conductivity 40 microsiemens. Fp.puerzli was also found in this biotope.

A spring close to Yabassi, western Cameroon. This has also been spelt 'Jahassi ' & 'Jabassi' in previous literature.

Western Cameroon in the Lower & middle reaches of the Wuri, Dibamba & Sanaga River drainage systems. This is the second largest distribution area of the subgenus.
Amiet 1987 found them at Nkondjock which is by the foot of the Bamileke Plateau representing the northern edge of distribution. He fished at Fopouanga on the south side of the plateau but failed to find them.
The eastern limit has yet to be defined in Amiet 1987 but it was thought to be at the natural barrier of the Ouem River.
The Sanaga River to the southeast in the lower drainage area was considered to be the edge of the sp. distribution in this direction but Amiet 1987 verified that they were 'abundant' near the sources of the Kondé River which is a small eastern bank tributary of the Sanaga River.
The southern limit appears to be the old Douala - Edéa road. From here they are replaced by A.loennbergii.
Replaced to the coast in the west by A.splendopleure.
Amiet 1987 found A.riggenbachi in a stream 'quite close to a river' which was inhabited with A.loennbergii at Dibombe.

Coastal rainforest streams & brooks flowing over ancient basement rocks & sand. Depth of water is reportedly 30 cm. Water temperature 22-32°C. They are found sympatrically with Fp.puerzli, Fp.amieti & A.franzwerneri also.

Size, this species is the largest of the Chromaphyosemion subgenus. According to Amiet 1987, the background colouration on the body has no metallic reflections, being green, blue, turquoise generally but occaisionaly yellow/green or mauve/violet.. The fine red carmine red punctuations are more noticeable than other species in the subgenus.

All the populations I have kept over the years have seemed drab in colouration & never showed themselves off as other species in the subgenus.

Huber in Killidata considers a method to seperate the species by the outer marginal band of the anal fin & the submarginal band of the caudal fin. Both being red.
Also, females are reported as lacking the distinctive 2 black horizontal lines in females.
This line is reportedly grey. I do not completely hold with this point of distinction as I have seen females with 2 bands. A photo above of Yabassi illustrates this.

Ahl described the species in 1924 from 4 specimens collected near Yabassi, eastern Cameroon. Holly examined the type specimens & changed some of the data in his redescription of 1930. These types were described as being 'a uniform yellow, with rows of faint spots in some of the fins' (ROTOW 1).

Scheel in BKA newsletter 76, December 1971 mentions populations BIV-GI (collected 25 km north of the junction) & BIV-YA (collected 15-17 kms north of the junction). The BKA had in circulation in 1971 the BIV-YA population which, according to Scheel was not as colourful the other population mentioned. This BIV-GI population soon became extinct in aquaria.

First distributed in the BKA in October 1972 from a BKA import containing 2 pairs.

Water incubation takes 15-18 days. Growth rate is a little slow with sexual maturity being attained at about 7 months. It has been reported that some young males can start to show colouration at the age of 3 months.

The first introduction to the BKA seemed to prove difficult in that a high proportion of eggs would fungus when collected. The natural method of leaving the eggs in the breeding tank proved more successful. It was reported at the time that young fish seemed to stop growing around 1" & later started growing again. Full maturity was observed to be about a year.

Dave Astbury's article mentioned in 'Populations' gives a report on breeding the Yabassi population..
He found this fish rather inactive & despite their size placed them into a 12x8x8" tank. Rainwater was added with a teaspoonful of salt per gallon. A clump of Java moss was placed in the centre with Riccia & Ceratopteris as floating plants. He recommended changing 20% of the water each fortnight.
For general maintenance 21°C is OK but for breeding a rise to 23°C is recommended. Eggs are laid in the Java moss & can be collected & placed in seperate tubs with fresh rainwater. It was noted that the addition of Acriflavine or other anti-fungicides were lethal to the eggs & would kill them overnight.
In this setup Dave collected 50-60 eggs weekly. Eggs hatched in 10-12 days. The fry have a yolk sac for 3-4 days. Infusoria was fed for the first few days graduating on to newly hatched brine shrimp.

Huber, in Killidata considers a wet incubation period of 3 weeks. First food can be newly hatched brine shrimp. First signs of sexing out noticed at 12 weeks with full maturity gained at 8 months.

Oliver Legros in BKA Newsletter No. 318 (March 1992) considered A.riggenbachi the slowest to sex out of all other then known Chromaphyosemion. The was particularly seen in the Yabassi population.

I had some wild fish in collected at Yabassi, December 2022. About 11 males & 3 females. These were put in a 2 foot square tank on system so water was continually being put into the tank at quite a high rate. The fish were quite happy with this & quickly grew on to a point they started laying eggs in a top mop. At first a lot went fungussed. As time went on fewer were lost & it became rare to find a bad egg.
The mop was also left to drop to the bottom of the tank but no difference in the amount of eggs produced. Five a day was the norm. I found the mop one day had been dragged by the water movement into the stream of water entering the tank. Egg production went up to around 20. This went on over the next few days with the mop in the same place.
As the fish became established fry started to appear in the tank & grew on unmolested by the adults.

Whilst many populations of this sp. have proved difficult I found the wild (& F1) Dibeng proved very easy to breed.