After Werner Herzog, a German aquarist who discovered the species.

Radda A.C. 1975.

Contribution to the knowledge of the Cyprinodonts of Gabon, with the description of four new species and one new subspecies of the genus Aphyosemion Myers.

Killi-News 118 (Seperate): 5-6, plates 10-11. (BKA)

4 cm (Radda & Pürzl 1987)

• D = 12-13, A = 13-14, ll = 29-30(+2) (Radda 1975)
• D = 10-13, A = 12-14, ll = 29-31(+2) (Radda & Pürzl 1987)

n = 17, A = 34 (Scheel 1981)

Mesoaphyosemion

herzogi (originally placed in the calliurum group).

• Aphyosemion calliurum ahli (non Myers 1933) Lambert & Géry 1968
• Aphyosemion batesii (non Boulenger 1911) Roman 1971
• Aphyosemion bochtleri Radda 1975
• Aphyosemion herzogi bochtleri Radda & Pürzl 1987
• Aphyosemion herzogi herzogi Scheel 1990

• Akoga (northwestern Gabon)
• Asseng
• Assok (northern Gabon)
• Doumandzou
• Ebebiyin, Rio Mami (Equatorial Guinea)
• Essong-Medzom (north
• ern Gabon)
• Médouneu
• Mintoum (northern Gabon)
• Nsessoum
• Ovan
• Zomoko (northern Gabon) GBG 92 / 26
• G 227
• GBG 93 / 32
• GBHL 86 / 1GWW 86 / 11
• GHG 83 / 2
• GWW 86 / 11
• LEC 93 / 22
• LEC 93 / 25
• PEG 93 / 15

• http://www.nakashima.org/ga_herz_h.htm Japan Gallery
• Zomoko http://www.nakashima.org/gaphyosemion Japan Gallery
• Zomoko http://www.garysfishroom.us Gary Bartell's site
• GWW 86 / 11 http://www.garysfishroom.us Gary Bartell's site

3 km north of Zoumoukou / 16 km north of Lalara on the road to Mitzic & Oyem, northern Gabon.

The inland plain of northern Gabon, southern Cameroon & eastern Equatorial Guinea. Found in the Ivindo (upper), Mvoung (middle) & Okano (middle) River drainages of northern Gabon. In southern Cameroon they are found in the Ntem River drainage. In eastern Equatorial Guinea they inhabit the Benito River drainage.

Collected in mountain brooks between Mitzic & Lalara. The water was clear & occasionally fast flowing.

Wild fish have been found not to take aquatic foods, instead relying on a diet of terrestrial insects (Amieti 1987).

Discovered by Werner Herzog & Franz Bochtler in 1972.

This species is one one the harder species of the genus to breed & are not recommended for the novice killie keeper. Males can be aggressive towards females & a larger tank with plenty of plant/mop/fibre is recommended. If possible use 2-3 females. Eggs can be left in the breeding tank which, along with the fry are left alone by the parents. As these fry grow they should be taken out & raised in seperate aquaria.

Incubation time in water is 12-14 days. Newly hatched fry are capable of eating newly hatched brine shrimp. They are slow growing & can take 7-8 months to reach sexual maturity, & this after regular water changes.

Ian Sainthouse in BKA newsletter No. 180, August 1980 reported that he kept this sp. in a 3-4 gallon tank with a gentle aeration sufficient only to disturb the water surface. Peat fibre was found to be the preferred medium to spawn in. Mops & Java moss were ignored. A pair will start to lay eggs at 5 months of age but 9 months is a better age to get reasonable egg production.
On hatching, fry were found to be quite large. They appeared to be selective in which foods they preferred. Micro worm were ignored but newly hatched brine shrimp was taken.

Rudiger Wagner reported on his observations in the BKA newsletter No.299, August 1990.
Two males & five females of the population from the type locality were placed in a 30 x 30 x 12cm tank, thickly planted with Java fern, Java moss & 4 spawning mops. The water was pH 6·5, DH 5. Live pond foods, Tubifex & frozen foods were fed & a few Ramshorn snails were added as scavengers.
Fish preferred to lay on the mops just below where the fibres are tied together. Ten eggs were collected in a week.
After a few days eggs were collected which were picked off with the fingers without damage. These were water incubated. Incubation took 2-3 weeks depending on temperature. Lower temperatures meaning longer incubation period. The hatch rate was high & this was the case if the eggs were treated with trypaflavin or not.
At 7-8 weeks of age the young started to die.
He tried the GBG 83 / 2 population. These layed about 10 eggs a week. Water was used from a spring at pH 6·5, DH 3. 50% water changes were carried out eevery 3-4 weeks. After water changes fish were keen to spawn. After a week egg production always fell. Again, many fry died along the way with only a few making it to adult size at the age of 5 years.
The fish house temperature was 20°C. The fish started to look distressed at 22°C. Lower temperatures were tried & over the winter months it fell to 13°C. As the temperature rose to 16-17°C eggs started to appear & 16 were collected. These were placed on moist peat. None of the eggs fungussed & only 2 fry died. Egg development time was 3-4 weeks. As the temperature rose to 20°C egg production ceased. A water change did nothing to improve things but another change 2 weeks later produced 12 eggs.
This batch were fed newly hatched brine shrimp as a first food. Growth was initially slow.

http://4d.biotech.wisc.edu/killifish/HerzogiMale1.jpg