Last week we received for the first time an unsusal shipment containing Distichodus unknown to us from Nigeria. The first determination was that they belonged to the species Distichodus rostratus. This species attains a maximum length of about 70 cm. We thought initially that all or fish would belong to the very same species, despite the fact that there are both spotted and striped animals, because it is known from D. rostratus that very young fish are initially striped, become spotted later and the fully grown fish is more or less uniformly coloured.
When picking up specimens for photos we saw that the differently coloured fish had a different shape of the head. And there was even one specimen of a third species with comparatively large spots and a completely different shape of the head.
Further study of literature showed that in fact we have three species. Only the striped ones are really D. rostratus. The spotted ones are in fact D. engycephalus, a species attaining about 40 cm in length; and the bycatch with the larger spots is a specimen of D. brevipinnis, which becomes 60-70 cm long.
Obviously the different species imitate each other during the juvenile phase. This gives a bigger security for the individual specimen against predators. The different shape of the mouth clearly show that the different species have different food preferences. So the fish in the school of mixed species have the advantage of more security but comparatively less competition for food than in a one-species school.
For our customers: D. rostratus has code 128103 on our stocklist. Please note that we exclusively supply the wholesale trade. Available in very limited numbers only!
Text & photos: Frank Schäfer
|Angaben zum Tier|
|Verfügbare Größe in cm||6-8|