Pseudochromis fridmani (Purple dotty back)

Diffusion

Pseudochromis fridmani, magnificently colored in purple, mainly lives in the northern area of the Red Sea constituting in that zone the most numerous representative of its kind. In the Indo-Pacific there is a very similar fish of the same kind but with a stockier aspect: its name is Pseudochromis porphyreus. However, this animal is not provided with the black ocular band and the coloured fins.

Description

Long and tapered body type, completely coloured in purple. Presence of a black band passing through the eyes. The fins are not transparent, but purple like the rest of the body.

Size

Pseudochromis fridmani may reach 7 centimeters in length.

Environment

Pseudochromis fridmani lives in a way strictly linked to the reef, occupying along the walls of the reef from 1 to 30 meters and, more rarely, even up to 60 meters in depth, territories sometimes densely populated. (Debelius, 1998, also reports 6 individuals per square metre). This circumstance allows them to be seen frequently in a group in the reef, even though, actually, they only occasionally live near some of their conspecifics (Debelius, 1998). So, not in group but in couple within small territories, which very often contain a recess with their eggs.

Feeding

Pseudochromis fridmani in nature mainly feeds on small invertebrates, while in aquarium it also very soon accepts frozen feeds and even those dried, that’s why it is free of food problems. In case of an inadequate administration of food and a consequent vitamin deficiency, a fading of the intense colour may occur, which is often considered as a sign of old age of the fishes. However, through a vitamin integration, this fading is usually reversible.

Maintenance in aquarium

For the reef aquarium, the Fridmans fish is ideal. It is preferable to keep it in couple, but only in tanks of over 500 litres it is also possible to introduce more couples. However, mortal fights occur very often, between the couples as well as between female and male. In the end, only the most vigorous couple remains. Within the genus Pseudochromis, P. fridmani is part of the less aggressive representatives, as precisely opposed to the similar species P. porphyreus that is able to develop violent aggressions against conspecifics. FossÅ & Nilsen (1993) report that P. fridmani occasionally feeds on small shrimps, which in normal circumstances is anything but probable. However, the Fridman fish, despite its reduced size, is a fully respectable “customer”. When it comes to defending its nest, in fact, it is able to drive away even much larger fishes.

Fridmani1

Reproduction, behavior 

For the well being of this fish, a natural setting up of the aquarium with several hiding places is important. That, after all, is true for all those belonging to the genus Pseudochromis, since they are very intelligent, lively and curious animals that continuously explore their territory. An individual of this genus, for example, has been observed while regularly moving from one part to the other in two aquaria communicating through a pipe. The food was administered in alternation, and the fish swam with absolute reliability through the communication pipe, always towards the aquarium where, in that moment, the food was introduced. During the formation of the couple, in mature individuals the two sexes are rather easily recognisable. The males present a ventral fin with a very pronounced point, while in the female it is just rounded or slightly angled. The courting and laying can be well observed in aquarium, especially when shells of tridacna or large snails, adequately perforated, are placed in specific points. As soon as “she” is ready for the laying, as recognisable by the slightly rounded belly, “he” starts to swim around her from a short distance. Shortly before brushing her, he inverts the swimming rushing towards the chosen nest. He repeats this procedure until the female starts to follow him. Sometime she plays hard for very long, in these cases the courting may also last several hours, but in the end the female follows the male in the nest and the laying takes place. However, after that, she has to keep away from the recess: the males guard the eggs, proving to be very aggressive in the surroundings of their nest! The lamp of eggs is small and compact, but after a few hours it swells, absorbing water up to two, three times its original volume (R. Brons). The eggs are ready for the hatching after 5, 6 days. The tiny larvae come out during the night moving away like planktonic organisms in the water, although probably not too far, thus explaining the diffusion of the species in the northern part of the Red Sea (R. Brons). The species lays the eggs in aquarium, and for several years it has been commercially reproduced in great quantity at various breeding centres. The growth of the larvae is obtained with enriched brachionuses, and then continues with the artemias. The end of the planktonic stage and the metamorphosis, during which the young fishes develop the typical colour of the species, takes place between the 25th and the 30th day of development (R. Brons). Nevertheless, the reproduction proves to be quite complicated and therefore only advisable to very skilled aquarists who have already reached success with other species.

Comment

Pseudochromis fridmani is named after its discoverer David Fridman, the multi annual curator of Coral World, who has realized his dream of building a subaqueous observatory and now, as a retiree, lives in Eliat, Israel.