Xenotilapia ornatipinnis Boulenger, 1901: The Pearl from the Deep

Description:

Xenotilapia ornatipinnis was described by Boulenger in 1901 using specimens caught at Kibwesi, Tanzania, on the central east coast of Lake Tanganyika. X. ornatipinnis can easily be distinguished from other species of Xenotilapia by having a very steep forehead and some very large oval eyes placed high on the head.

Sexual dimorphism is well developed; the male has a beautiful dorsal fin adorned with a black and yellow margin, and a light reddish spot in the anterior part of the fin. The anal fin likewise has a yellow margin with a broad white band, which depending on the angle of the light hitting it, sparkles in different reddish colors. The caudal fin is forked with pointed lobes and is colored with broad yellow and white bands, and the ventral fins have a clear whitish blue color; the pectoral fins are clear. The males’ silvery colored flanks are lined with six alternating vertical bands; three yellow and three consisting of sparkling iridescent spots, the latter gives the body an overall pearly appearance.

The females does not have the males beautiful colors, but have an overall silvery coloration, with 5-7 indistinct black spots in the dorsal fin

Xenotilapia ornatipinnis is a rather large Xenotilapia and males may acquire a total length of 13 cm, while the female stays a little shorter. It has a lake-wide distribution and no geographical variants are known.

Xenotilapia ornatipinnis in the wild…..

Not much is known of the life of Xenotilapia ornatipinnis in Lake Tanganyika, and to my knowledge no picture has ever been published that shows it in its natural habitat. What is known is that most individuals have been caught in trawls in deep water, some down to a depth of incredible 160 meter (525 feet), but collection in much shallower water at a depth of 5 meter has also been recorded (Poll 1956). This great span in depth distribution could very well be a expression of daily migrations, as has been documented in species of the genus Trematocara (Konings 2003).

Measurements of the digestive tract in a 115 mm long individual showed a rather short tract with a length of app. 90 mm, indicating a carnivorous diet, and investigations of the stomach content has in fact also revealed Copepods, Ostracods and insect larvae, besides sandgrains and mud (Poll 1956)

Poll also mentions that the length of the caught individuals of Xenotilapia ornatipinnis varies considerably and concludes that reproduction is not related to a periodic cycle, but probably is carried out at all the times of the year (Poll 1956).

The adaptation to a life in the deep are obvious when one sees the large eyes and quite possible are the silvery lines on the flank of the males an adaptation as well, as they properly serve as a recognition mark to enable females to find their mates in the deep and dark water (Konings 1998).

…..and in the aquarium

Fortunately more are known of the behavior of Xenotilapia ornatipinnis in the aquarium than in the Lake. It was first time exported to Europe under the name of X. sp. "Burundi" in 1990 (Eysel 1990) and arrived in the US as well at app. the same time (Smith 1992).

In the aquarium Xenotilapia ornatipinnis turns out to be a rather calm species; displaying males will only chase, but never harass or damage each other. The bottom of the aquarium should consist of a layer of fine sand and between the open sandy sections small rocks should be placed acting as territory boundaries. The stones should be smooth and water rolled – no sharp edges here! The bottom of the aquarium should be no less than 120 x 50 cm (3.90 x 1.65 feet). In a tank with this volume it is possible to contain a small group of approximately 6-7 individuals. It advisable to have more than one male – if just one male is being held, he seldom shows his true colors. As X. ornatipinnis is a carnivore it should be feed with frozen food like artemia, cyclops, mysis, black mosquito larvae and small chopped up shrimps. It feeds in the typical sand-dweller fashion by taken mouthfuls of sand, filtering it and swallowing all eatable, and then expelling the sand again through the mouth and gills.

Ideal companions would be some calm free-swimming species like Paracyprichromis nigripinnis or P. brieni. If the aquarium is sufficiently large, a pair of one of the bi-parental Xenotilapia species could be added as well

Most schooling species of the genus Xenotilapia can at times react very nervously in the aquarium, and X. ornatipinnis are no exception. In order not to scare the fishes, approaching the aquarium should be done quietly; especially if the fishes are disturbed at night they could react very nervously and panic, trying to jump out of the aquarium or hurt themselves against stones or the glass of the aquarium. The capture and transport of these cichlids is also not the easiest thing and precaution should be taken not to damage the large eyes; the fish must be quickly caught and the time in the net should be kept at an absolute minimum.

Reproduction

Xenotilapia ornatipinnis is a maternal mouthbrooder which can be sexed when they reached a length of app. 5 cm as the colors of the males begin to be seen. The males occupy a small territory which is not marked visibly with a nest, as seen in other species sand-dwelling species. The males display for each other and every passing female, trying to lure the females to spawn while they chase other males away. The males get an intensified coloration and a black bar in the eyes will appear. If a male succeeds luring a female, they will circle around and the female will eventually place some eggs which are then quickly fertilized by the male and then quickly taken in by the female. The female broods the eggs for app. 18 days before the fry are released; no further brood care has been reported. Fry should be fed with newly hatched artemia, frozen bosmins and cyclops.

Conclusion

Xenotilapia ornatipinnis is a stunning sand-sifter that if given the right conditions will reward its owner with its beautiful displaying and interesting behavior and for sure be the Pearl from the Deep!