The spotted killifish (''Nothobranchius orthonotus'') is a small, short lived species of fish, an

African rivuline Nothobranchiidae are a family of bony fishes containing roughly 300 species, also known as African rivulines. They are small killifish, usually measuring about . They are limited to Africa, living in fresh water but being also somewhat salt-tol ...

from the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Nothobranchiidae Nothobranchiidae are a family of bony fishes containing roughly 300 species, also known as African rivulines. They are small killifish, usually measuring about . They are limited to Africa, living in fresh water but being also somewhat salt-tol ...

. These fish are native to many isolated freshwater pools located in the savannah depressions of east Africa, specifically Malawi, Mozambique, Zimbabwe, and South Africa. This species of fish occurs in ephemeral waters and killifish eggs can survive long periods of dehydration. The word killifish likely comes from the Dutch ''kil'' for kill (small stream).

Diet

The spotted killifish consumes both aquatic invertebrates and vertebrates, its diet consists mainly of juvenile lungfish (''

Protopterus annectens The West African lungfish (''Protopterus annectens''), also known as the Tana lungfish or simply African lungfish, is a species of African lungfish. It is found in a wide range of freshwater habitats in West and Middle Africa, as well as the nort ...

'') and larval amphibia. In addition to these, this species also consumes a relatively high proportion of insect

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e from the

orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Odonata,

Coleoptera Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

and Ephemeroptera. Diets such as these may be deemed as profitable for the trade-offs in item size and ease of catching.

Life Cycle and Reproduction

The spotted killifish, typically of the genus ''

Nothobranchius ''Nothobranchius'' is a genus of small, freshwater killifish, classified in either the family Nothobranchiidaevan der Laan, R., Eschmeyer, W.N. & Fricke, R. (2014)Family-group names of Recent fishes.''Zootaxa, 3882 (2): 1–230.'' or a more inc ...

'', are adapted to annual desiccation of their habitat. The fishes hatch at the start of each rainy season, and continue to grow very quickly. Within a matter of a few weeks, these fish reach sexual maturity, and reproduce daily, with females laying up to 50 eggs each day. From here, the eggs are spawned into a layer of rock or soil beneath the surface of the ground, and remain there after the pool has dried up. Even with a dry environment, the embryos are able to exist in developmental suspension until the starts of the next wet season.

Characteristics

Fish with the genus ''Nothobranchius'' show a striking level of sexual dichomatism, where the males portray bright colors, and the females are dull. The adult spotted killifish is one of the largest of its genus, and can grow up to in length.

Habitat and Ecology

The spotted killifish is native to isolated freshwater pools located in the savannah depressions of east Africa, specifically Malawi, Mozambique, Zimbabwe, and South Africa. This species was found to share these pools with '' N. furzeri'', '' N. kadleci'' and '' N.rachovii'', all congeners. The natural environments inhabited can range from non-vegetated and shallow with cloudy water, all the way to densely overgrown pools, that are fairly deep and have clear water. This species may also be present in swamps intermittently connected to floodplains. Given the lifecycle of the spotted killifish, it has adapted to varying dry and wet weather conditions that persist in this part of the world. However, due to recent anti-malarial and tsetse fly spraying programs, the populations of spotted killifish are becoming threatened. Though this species is threatened, it is at lower risk, and not yet in need of acts of conservation given that the threats are localized.

Naming

The spotted killifish was originally described in 1844 as ''Cyprinodon orthonotus'' by Wilhelm Peters with the type locality given as Quelimane in eastern Mozambique. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

is derived from ''orthos'' meaning "straight" and ''notus'' meaning back, referring to the straight dorsal profile of this species.

References