Palmqvist’s Nothobranch is one of several species in which the caudal fin is blood-red throughout. As in so many other Nothobranchius species, the body coloration shows variation, depending on locality of origin. Generally, it has a bluish body with a network of red lines covering it. Females are smaller and duller in color than the males.
This colorful annual species, known in the hobby since the mid- 1910s, is one of the best-known representatives of its genus. Nothobranchius species are highly variable and often cause confusion with regard to precise identification. Some aquarium strains are also known. Like many other killifish, it is available only occasionally in general aquatic outlets.
This species has similar oblique body bands to A. chaperi (Chaper’s Panchax). As its common name suggests, it has six of these vertical bands. It is extremely variable, both in color and body patterning, and there are five known subspecies, each exhibiting variability according to location.
The Blue Panchax is one of the earliest species imported into Europe (1899). Despite this, it has never become as widespread within the hobby as its obvious beauty deserves. It has a greenish body with blue coloring along both sides that serves to highlight the outline of the scales.
Two subspecies of A. chaperi are known: Chaper’s Panchax (A. c. chaperi) and Schreiber’s Panchax {A. c. schreiberi). Both have varying numbers of backward-slanting, narrow, oblique dark bands that are more pronounced in females than in males. However, in both subspecies of A. chaperi the body is somewhat sturdier than in A. annulatus (Clown Killifish), and the caudal fin lacks the central fin ray extensions.
Traditionally, the Clown Killifish and its closest relatives have been classified as Epiplatys. In 1990, following an earlier paper on the subject, Scheel (see Further Reading) placed Epiplatys within Aplocheilus. Owing to distinct body patterning and unique color distribution on the caudal fin, along with some skeletal and behavioral differences, Scheel also regarded A. annulatus as in a sufficiently “isolated position in Aplocheilus” to warrant its own subgenus, Pseudepiplatys (already considered as a valid genus by some earlier authors).
Blue Gularis is another species of killifish that has a number of different color forms. However, it is not split into subspecies. While possessing some blue (as indicated by one of its common names), most forms exhibit attractive red patches and stripes on the body.
The males of some populations of this species, such as those from southern Togo, possess a great deal of blue on their bodies, hence one of the common names. Confusingly, some other populations from the same region are orange-red. Most populations from other locations contain varying amounts of blue, orange-red, and reddish brown.
The Red-seam Killifish is a stumpier species than Aphyosemion australe (Lyretail), and it lacks the long extensions to the tail that are characteristic of its relative. Several naturally occurring color forms are known. In this species males are far more colorful than the smaller females.
This splendid fish first made its appearance in the hobby around 1913. It is one of the longer-lived killies—a life span of around three years is common. Only mature males exhibit the characteristic lyre-shaped tail that gives this species its common name. Several naturally occurring color forms are available as well as some cultivated ones.