Metriaclima

The meaning of the name Metriaclima – and the debate with Maylandia

Within the world of aquatics and ichthyology (the study of fish), there has been a long-standing debate about the correct scientific name for a genus of colorful mbuna cichlids from Lake Malawi. These fish are very popular among aquarium enthusiasts because of their vibrant colors and interesting behavior. The controversy revolves around two scientific names: Metriaclima and Maylandia.

The meaning of Metriaclima
The name Metriaclima was introduced in 1997 by Stauffer, Bowers, Kellogg & McKaye. The name is composed of two Greek words:

metrios means “moderate” or “average”,
clima (or klima) means “slope” or “elevation.”

Together, Metriaclima refers to the “moderately sloping head” that is characteristic of the fish within this genus. It is a reference to an anatomical detail that the authors considered a distinguishing feature.

The origin of the name Maylandia

The name Maylandia was proposed earlier, in 1984, by Meyer & Förster. This name is a tribute to Hans Joachim Mayland (ca. 1928–2004), a well-known German aquarist and author of books on aquarium fish. The suffix -ia indicates “belonging to,” so Maylandia literally means “belonging to Mayland.”

The taxonomic debate

The core of the debate is whether Maylandia is valid as a scientific name. Critics argue that when it was published in 1984, Maylandia did not comply with the rules of zoological nomenclature: in particular, no formal diagnosis (a scientific description of distinguishing characteristics) was provided. According to this view, Maylandia is therefore invalid or unavailable, and Metriaclima would be the correct name.

Others, including Eschmeyer’s Catalog of Fishes—an authoritative source in ichthyology—consider Maylandia to be valid because it was published first. In that case, the older name takes precedence over the newer one.

Practical use in the aquarium world

In practice, scientists, aquarium associations, and databases use different names depending on their position on this taxonomic issue. However, Metriaclima is now more common in many publications and commercial contexts, partly because this name is based on a clearly defined description.

In our database, we have chosen to use the name Metriaclima, in accordance with the view that this name is better substantiated according to the rules of taxonomic nomenclature.

Number of species

The genus Metriaclima comprises some 32 officially described species and a number of species that are still awaiting description. The list below contains the species that we have not yet included in the database. Below that, with photos, are the species that we have already added.

Metriaclima benetos
Metriaclima cyneusmarginata
Metriaclima flavicauda
Metriaclima glaucos
Metriaclima hajomaylandi
Metriaclima lanisticola
Metriaclima lundoense
Metriaclima mbenjii
Metriaclima midomo
Metriaclima mossambica
Metriaclima nigrodorsalis
Metriaclima nkhunguensis
Metriaclima pambazuko
Metriaclima usisyae
Metriaclima xanthos
Metriaclima zebra

Species not yet described:

Metriaclima sp. ‘red top gallireya’
Metriaclima sp. ‘kingsizei lupingu’
Metriaclima sp. ‘aggressive greyhead’
Metriaclima sp. ‘agressive zebra maleri’
Metriaclima sp. ‘chinyankwazi’
Metriaclima sp. ‘elongatus linganjala’
Metriaclima sp. ‘kingsizei masimbwe’
Metriaclima sp. ‘aurora bevous’
Metriaclima sp. ‘zebra patricki’
Metriaclima sp. ‘lime nkhomo’
Metriaclima sp. ‘zebra gold’
Metriaclima sp. ‘aggressive bars’
Metriaclima sp. ‘black dorsal mbenji’
Metriaclima sp. ‘cave manda’
Metriaclima sp. ‘dumpy tanzania’
Metriaclima sp. ‘dumpy’
Metriaclima sp. ‘elongatus bee’
Metriaclima sp. ‘elongatus chailosi’
Metriaclima sp. ‘elongatus chidunga’
Metriaclima sp. ‘dumpy chitimba’
Metriaclima sp. ‘elongatus ngkuyo’
Metriaclima sp. ‘estherae blueface’
Metriaclima sp. ‘hajomaylandi pombo’
Metriaclima sp. ‘lanisticola north’
Metriaclima sp. ‘lime jalo’
Metriaclima sp. ‘lime’
Metriaclima sp. ‘mbweca’
Metriaclima sp. ‘taiwan masimbwe’
Metriaclima sp. ‘taiwan’
Metriaclima sp. ‘zebra mbowe’
Metriaclima sp. ‘zebra ruarwe’