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Altolamprologus calvus (Black)


Article by Daniel Lesich

Species information

Species: Altolamprologus calvus (Black)

Synoma: Lamprologus calvus

Common name: Black Calvus, Calvus, Black Pearl Calvus.

Origin: Lake Tanganyika Africa

Localities/Morphs: Zambia and southern Zaire, Lake Tanganyika

Maximum size: males can reach 15cm and females reach 10-12cm

Natural habitat: Rocky areas where there is sufficient cover and adequate breeding grounds as the Calvus is a shy fish and very secretive.

Natural foods/prey: small fish, fish eggs and invertebrates

Water chemistry in the wild: pH - 7.8 to 8.5 GH - 7 to 12 KH - 10 to 15

Predators: larger fish when young.

Brood size: 70-300 depending on the age of the fish

Breeding method: substrate spawner ... uses shells or crevices in rocks to breed

Husbandry requirements

Minimum tank size: i would recommend that a 3x14x18 be the absolute smallest tank to house a breeding pair.

Sex ratio: 1m to 1f or can be kept in a breeding harem with multiple males and females but a large tank is required for this.

Sex differences: Males tend to be bigger if out of the same batch of fry

Tolerance of conspecifics: can get very aggressive

Tolerance of heterospecifics: ok - can be kept with other fish in a community tank and rarely bothers with other fish other than its own kind. recommended tank mates would be Frontosa but only if the Calvus was a decent size, Cyprichromis leptisoma and any other well tempered fish.

Water chemistry in aquaria: pH: 8.0-8.9, general hardness 10-20 gH, carbonate hardness 9-12 dKH

Temperature range: 23-27 degrees Celsius, does not tolerate slightly higher temperatures very well. optimum is 25

Foods accepted: omnivorous, they will take almost everything offered. Pellets, flakes, live black worm, and frozen brine shrimp. foods containing animal products such as beef heart should be avoided as its detrimental to the calvus's health as the fat will be stored in the liver of the fish and then degenerate causing ill health and death

Special requirements: no special care is required with these guys as they are quite hardy. only that the water temperature should rarely exceed 29 degrees Celsius as anything higher will be fatal and high water quality is a must.


Some interesting points:

  • I must start in saying that the Calvus and its closely related cousin the Altolamprologus compressiceps have fast become my favorite species of fish i keep. now i'm not going to say that it was love at first sight as the first time i saw the Calvus i thought they were the most hideous and prehistorically looking ugly creatures i had ever seen, but that fast changed after constantly watching the interesting behavior of a friends Calvus, and soon fell in love with them. then i just had to have some and soon acquired 7 2cm fry.
  • I soon found out how painstakingly slow growing the Calvus is and after 6 months they have only grown 2cm but in saying that and studying them i have found that i have 3 males and 3 females due to the size differences between them and also their social behavior.
  • unfortunately i lost one due to it jumping out of my tank and have found that the Calvus is infamous for jumping out of tanks so precautions are necessary to prevent them from doing so as it is heart breaking finding them on the floor so all holes in the tops of tanks should be covered even the smallest ones.
  • from all the research i have done there seem to be only 3 different colour morphs of the Altolamprologus calvus and they are the black, yellow, and white. i have only seen the white and black forms available in Australia so far but strongly recommend keeping different colour morphs separately to prevent hybridization.
  • The Calvus is a very intimidating looking predator and many people think they are tank destroyers but this is not the case and have found that they will very rarely show any interest in other fish and concentrate more so on its own kind. the Calvus will happily coexist with other tank mates providing the tank mates are chosen wisely.
  • one very unusual characteristic of the Calvus is its defense mechanism which is when another fish attacks the Calvus will bend its body towards the attacker to allow it to bite and once the aggressor has bitten it soon finds that the Calvus has spiky scales which shreds the attackers lips and teaches it to be weary in attacking again.
  • one last behavioral characteristic of the Calvus is its hunting technique. the Calvus will hover and cruse looking for prey and when food is found it stops and slowly lines up for the kill. the Calvus will slowly glide all the while with its eyes on the prey and within a blink of and eye using a sucking motion the tasty morsel is gone. this is a technique used in the wild in catching prey in cracks and crevices where a fish could never normally reach and with the Calvus specially developed mouth structure it allows it to suck prey from the smallest hard to reach spots.
  • the only characteristic which i have not yet had the pleasure of witnessing is the breeding ritual. there are many different ways that many different people have successfully bred this species but i unfortunately can not input any useful information other than a caution on using shells for breeding purposes with Calvus as i have heard from friends once the Calvus reaches a certain size the female can actually get stuck in the shell and die so the alternative to using shells would be ceramic or porcelain (glazed) pots which are large enough for the female to enter but preventing access by male but also large enough so that the female would not get stuck..
  • in conclusion the Calvus is an extremely enjoyable and interesting fish to keep and though the only draw back is the age it requires to reach sexual maturity 2.5 years.
  • i love these guys and would find any fish house collection incomplete without these guys so go out and get some you will not regret it.


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