The White Pearly CalvusAltolamprologus calvus (previouslyLamprologus calvus) is unusual with its very laterally compressed body. This shape allows it to squeeze into the tight crevices and deep recesses within its rocky domain. There it hides and searches for prey. Its natural foods consists of small fish, fish fry, eggs and small aquatic invertebrates found deep in the rocky fissures. This fish can easily slip in and then simply "suck" these morsels into its large mouth.
It is found in the southwest regions of Lake Tanganyika, Africa but there are a number of geographic variants. These each have very interesting colors depending on its location. Some may eventually prove to be distinct species or a subspecies. The body colors will vary between a black to a light whitish gray,and be with or without a yellow cast. There is a dark vertical striping that is most apparent in the front part of the body, and bright spots starting at about the pelvic fins going back onto the tail. Color patterns of the varieties can range from being black with white and light blue accents, to white with dark brown accents. There are reportedly "orange" and "tiger" varieties too, but these are most likely crosses.
This cichlid has a scaleless area on its forehead right between the eyes. Hence its species name "calvus" means "bald" in latin. Common names it is known by include Calvus Cichlid, Pearly Compressiceps, Pearly Lamprologus, and Pearly Calvus. This scaleless area on its forehead feature along with its colors and locality have led to a number of descriptive common names as well such as Black Calvus, White Calvus, White Chaitika, Tanganyika Blackfin, Congo Blackfin, Yellow Calvus, and Black Pearl Calvus to name a few.
It is closely related to its very similar looking relative, the Compressed Cichlid Altolamprologus compressiceps. Both of these species are compressed laterally, and although they look much the same there are several differences. The Calvus has a longer, shallower body giving it a more streamlined appearance. The Compressiceps is thicker in body width with a higher back, and it has a sloping forehead with a blunt upturned snout. The color the Calvus is brightly spotted with less distinct vertical barring while the Compressiceps has a bold stripes with very subdued, indistinct spots. The Calvus is somewhat smaller, attaining a length of about 5 - 6 inches in length, while the Compressiceps can reach up to 6 - 7 inches.
This is a good fish for both the intermediate and experienced cichlid keeper. It is moderately easy to care for as long as regular water changes are done to keep the water quality optimal. An aquarium best suited to this fish would be a minimum 40-50 gallons with a sandy bottom or very fine gravel substrate, and lots of rock formations for hiding places. Though plants are not essential, they do not burrow and will not harm them.
Being of a more peaceful disposition than a lot of cichlids, they are great for a peaceful Lake Tanganyika community environment. They mostly just mind their own business. They can be kept in pairs or in groups and are generally peaceful toward those of the same species. However if kept in a very large tank, they will establish a territory and chase conspecifics out. They will tolerate peaceful cichlids of a different genus.
The White Pearly Calvus have a laterally compressed body with a relatively high back and a steep forehead. This unique shape allows them to root out prey from rocks and crevices. They have scales that are very thick and with serrated edges. When threatened they will curve their body toward the enemy which exposes the scales. These scales are quite sharp and can rip up the lips of a biting rival. Males have longer fins once they mature. This is a slow growing, long-lived fish. They commonly grow between 4 - 6 inches (10 - 15 cm) in length, with males being the larger of the two and females being smaller. With good care it live about 8 - 10 years.
The body has dark vertical stripes that are most obvious in the front part of the body, with the back part being speckled and the stripes fading in the background. Depending on the variety, this cichlid can be black with white and light blue accents or white with dark brown accents. There are reportedly "orange" and "tiger" varieties too, but these are most likely crosses.
All cichlids share a common feature that some saltwater fish such as wrasses and parrotfish have and that is a well-developed pharyngeal set of teeth that are in the throat, along with their regular teeth. Cichlids have spiny rays in the back parts of the anal, dorsal, pectoral, and pelvic fins to help discourage predators. The front part of these fins are soft and perfect for precise positions and effortless movements in the water as opposed to fast swimming.
Cichlids have one nostril on each side while other fish have 2 sets. To sense "smells" in the water, they suck water in and expel the water right back out after being "sampled" for a short or longer time, depending on how much the cichlid needs to "smell" the water. This feature is shared by saltwater damselfish and cichlids are thought to be closely related.
The Calvus Cichlid is a carnivore. They are a slow growing predatory fish that in the wild will feed on eggs, fry, small crustaceans, insect larvae, and smaller fish. In the aquarium they will eat live foods such as mysis shrimp and earthworms. They may also eat prepared foods such as freeze dried krill, frozen foods (such as brine shrimp or blood worms), as well as protein tablets.
Feeding tubifex worms is not suggested due to possible diseases and pathogens that may be transferred to your fish. Also avoid mammalian meat. Feed 2 to 5 portions of food a day in smaller amounts instead of a large quantity once a day. All fish benefit from vitamins and supplements added to their foods.
Do normal water changes of 10% to 15% a week, or more frequent changes depending on the nitrite/ammonia levels and stocking numbers. The Lake Tanganyika cichlids cannot handle large water changes very well unless the new water chemistry closely matches the water they are in. If a large water change is needed, changing 15% every couple of days should bring water back to normal. This inability to tolerate large water changes is due to Lake Tanganyika being very deep and the water tends to stay stable.
The Calvus Cichlid is active and will swim in the bottom and middle areas of the aquarium. A minimum of 20 gallons for small juveniles and 40 - 50 gallons for adults is suggested. A larger tank, up to 100 gallons, would be required if mixing with other species. They do fine in either freshwater or brackish freshwater but need good water movement along with very strong and efficient filtration. Lake Tanganyika is a very oxygen rich lake so bubblers need to be going day and night, even if there are plants. Regularly check nitrates and ph, nitrates should be no more than 25 ppm and a pH less than 7 is not tolerated. In addition keep an eye on total hardness and carbonate hardness. Avoid overfeeding and overstocking.
Lake Tanganyika is the second to largest lake in the world, thus contributing to a low fluctuation in temperature and pH. All Tanganyika cichlids need stable temperatures kept within acceptable limits and lots of oxygen to survive. Temperatures under 72° F and over 86° F for too long is not tolerated by many of these fish. When treating for ich, a few days at 86° F is acceptable. The lake is also consistently alkaline with a pH of around 9, and very hard at about 12 - 14° dGH. In the aquarium most Tanganyika cichlids are fairly adaptable as long as conditions are close to these ideal ranges. Most important is that their water chemistry doesn't change much over time. The water needs to be well buffered and maintained with small, regular water changes.
Salt is sometimes used as a buffering agent to increase the water's carbonate hardness. An alternative buffering approach is to use a chemical filtration method, where the water passes through layers of crushed coral or coral sand. Interestingly, Tanganyikan cichlids also need iodine for the thyroid to function properly to regulate growth and development, and which can be achieved by adding iodized table salt to the water. Although rift lake cichlids need hard alkaline water they are not found in brackish waters. This cichlid has some salt tolerance so can be kept in slightly brackish water conditions. However it not suited to a full brackish water tank. It can tolerate a salinity that is about 10% of a normal saltwater tank, a specific gravity of less than 1.0002.
They need a lot of rocks and cave formations but also need plenty of open swimming areas. Provide a sandy or very small sized gravel substrate, though a sandy bottom is preferred. Sand used for salt water tanks can help keep the pH up as well as the addition of crushed coral. Crushed coral and aragonite sands do tend to dissolve easier than salts. They need a lot of rocks piled up to create cave formations. Plants are not essential though they do not harm them, nor do they burrow.
The White Pearly Calvus has been bred in captivity. This fish is an egg layer and the males are 1/3 larger than the females. Start with 4 to 5 fry or juveniles and grow them out in a 20 gallon tank. They will pair up in about 2 years and can be then used to breed. The females picks a spot that is too small for the male to enter. The White Pearly Calvus likes to spawn in tight spaces, and seems to especially like tapered ceramic cones called "boester bells". Shells that the male cannot fit into work well too.
The female will lay about 75 to 200 eggs and the male release sperm at the entrance of the cave. The eggs are stuck to the side of the cone or other spot. They differ in color and can be yellow, orange or amber. Both parents will fan the milt toward the eggs to fertilize them. After the eggs are fertilized, the female will fan and guard the eggs inside their "home" and the male will patrol outside.
In a little over a week the fry will hatch and move out on their own. The male will try to eat the fry once they are hatched, so many aquarists will put the "cave" or shell in another tank with the female after the eggs are fertilized. The fry will stick close to the bottom, so water and substrate must be especially clean. Some aquarists remove the fry a week after hatching and put them in a 5 gallon tank with a sponge filter.
The fry can be fed Hilkari First Start, Cyclopeeze, baby brine shrimp, finely ground earthworms, and brine shrimp flakes. Newly hatched baby brine shrimp seems to contribute to a higher survival rate. Doing 25% water changes 2 to 3 times a week is suggested to keep fry healthy. The larger fry will eat their smaller siblings. Within a month some stripes will appear, and in 2 months the larger fry will be 1/2" long and develop the body shape typical of the parents. The fry take 2 years to reach 2.5".