Aphyosemion exigoideum Radda & Huber 1977

A.exigoideum. Photo courtesy of Ed Pürzl

Meaning of Name

To resemble exiguum.

First Description

Radda A.C. & Huber J.H. 1977.

Cyprinodontiden Studien in Gabun - V. Das Tiefland West-Gabuns und die Mayumbe-Berge.

Aquaria 24 : pages 141-143 (some publications quote pages 137-150) figure 2, 6.

Size

5 cm

Meristics

D = 11-12, A = 13-14, D/A = +5-6, ll = 29-31 (Radda & Huber 1977)

Karyotype

n = 11, A = 21 (Scheel 1981)

Sub-Genus

Mesoaphyosemion

Group

striatum

Synonyms

None

Populations

  • EBT 96 / 23
  • G76 / 30 ( Ngoudoufola )
  • G76 / 31 ( Mandilou )
  • BBW 00 / 2
  • BBW 00 / 3 (possible corruption BWW)

 

Mandilou
Fish I kept early '80's

A.exigoideum circulating in the US around 1980. Photo: Courtesy of Lennie MacKowiak

Ngoudoufola.
Photo courtesy of Maurice Chauche & the KCF website.

BWW 00 / 2 male
Photo courtesy of Vasco Gomes

BWW 00 / 2 female
Photo courtesy of Vasco Gomes

BWW 00 / 2 taken at the 2003 BKA convention.
This fish had the code BBW attached which is an error.

Mandilou. Wild fish.
Photo courtesy of Ed Pürzl

Mandilou. Wild fish.
Photo courtesy of Ed Pürzl

 

Ngoudoufola http://www.nakashima.org/gaphyosemion_exigoideum_ngoudafola.htm Japan Gallery

Type Locality

A little confusing as both locations are given as the type locality in various publications. Wildekamp in 'World of Killies 1' states Mandilou, where they were found in a small brook in the rainforest. Other reports state:-

Ngoudoufola. A broad river.

Distribution

Fairly restricted to the Ngoudoufola - Mandilou area of Gabon where they inhabit the middle N'Goumé River drainage.

Habitat

Brooks, swampy areas, small rivers & forest streams.

The Mandilou location is still water with a DH of 0·5.

Measurements taken at Ngoudoufola were pH 7·5, DH 12, water temperature 21°C (also measured at 21·9°C). This biotope was a broad river 12 - 25 metres wide with a water depth of 15 - 30cm.

Distinguishing Characteristics A.exigoideum is easily recognisable from other Aphyosemion sp. by their bright red colouration which is quite heavy especially on the Mandilou population which has a broader red crescent on the caudal fin.
Colour/Pattern Variability
Fairly low. This sp. has a small distribution area. Variation has been reported in the outer margins of the caudal fin which can be bluish white or yellow (blue phase & yellow phase).

Some drawings of fish I kept early '80's
History

Collected by Dr.J.H.Huber & A.C.Radda on their expedition to Gabon in July 1976 at Ngoudoufola & Mandilou in a small forest river.

Radda took many pairs to the 1978 AKA Convention.

Ed Pürzl brought this sp.( G31/76 ) into the UK in 1978 & these were distributed in the Kent & Wessex area.

Breeding Notes

This sp. is a non-annual with a 16 - 21 day incubation period (some reports state 12-15 days). Experimentation has proved that eggs can be successfully dry stored for 3 - 4 weeks. Fry which I raised appeared very slow growing but sexed out evenly. When fed exclusively on Daphnia it was noted that the males lost all their bright red colouration & became a washed out pink colour.

The fry I raised were slow growing but evenly sexed bred in water of pH 8, DH 10. Other reports suggest sexual maturity is attained as little as 4 months.
Cooler water in the low 20°'s will induce spawning.
I did try putting eggs on wet peat which worked OK. Wetting when the eye could clearly be seen.

Fred Wright reported in a BKA I/P that eggs dry or semi dry required at least 16 days before attempting wetting. Fry were reportedly in need of infusoria as a first food. Growth was not rapid suggesting a long lived fish.

Peter Watkins in BKA newsletter No.176, April 1980 gave a breeding report stating that eggs were found in floating Riccia & bottom mops. Water was hard tapwater (DH 15, pH 7·8). In this hard water the eggs eyed up well but many died after 10 days. He later placed the eggs in rainwater with better results.

Diameter of Egg 1.3 - 1.6mm.
Remarks

Fred Wright regarded this as one of the most colourful sp. from the Gabon - Radda/Huber collection & I'm inclined to agree with him. Not a prolific spawner but well worth the effort in breeding a few pairs.
When I fed my fish exclusively on Daphnia I found they lost all their red colouration & became a washed out pink colour.
Males can be aggressive to each other. Be warned! This sp. is a good jumper.
I would recommend regular water changes with this sp. as they do not tolerate a build up of disolved metabolic waste in the water.