The Peacocks of Lake Malawi
by Marc Elieson
The so-called Peacock cichlids of Lake Malawi have achieved sustained popularity among aquarium hobbyists for more than three decades. The Malawi Peacocks possess several characteristics that have kept them in perpetual demand. First and foremost, Peacock
Another factor contributing to their popularity is their relative peacefulness with other fish, making them suitable candidates for a community-type aquarium provided the other tankmates are selected appropriately (more below). Peacocks also breed readily and are relatively undemanding aquarium residents. These attributes make Peacocks appealing to both the beginner and advanced hobbyist.
The Peacocks of Lake Malawi consist only of those fishes from the genus Aulonocara. Members of this genus are characterized by a remarkably enlarged lateral line system. The lateral line, or lateralis, is a line of perforated scales along the flanks of a fish which lead to a pressure-sensitive nervous system. Specialized cells within the lateralis, called neuromasts, enable a fish to detect vibrations and electrical impulses in the surrounding water. The lateralis is thus essential in allowing a fish to detect potential predators as well as prey (Loiselle 1985). Peacocks are particularly pressure sensitive due to an enlargement of the facial pores and an extension of the lateral line onto the jaw. The squamation
Living in deep and dark water, the Peacocks have developed and rely on their enhanced lateralis sense to hunt for food. Aulonocara are benthic insectivores and are therefore almost always found along the sandy bottom of the lake. They hunt sand-dwelling invertebrates with the aid of these enlarged pressure sensitive tubes in the flesh of their jaws. They hover motionless above the sand by just a few millimeters. With the very sensitive and enlarged sensory pores on the lower part of their head they are able to detect the micro-movements of tiny invertebrates in the sand. They hover motionless until such a prey's movements are detected. Such a detection is followed by an instantaneous bite into the sand. Sand is then strained for food by shooting it out the fish's gills while retaining the acquired treat (Konings 1995).
This hunting technique has not been documented in the aquarium, most likely due to the absolute lack of insect larvae and other small crustaceans living in the aquarium substrate. They often sift through the sand after
It is important to consider Peacocks' natural habitat when contemplating how to arrange the aquarium they will inhabit. Sand is the substrate of choice. Gravel with its sharp edges may irritate their gills since they frequently chew and sift the substrate after each feeding. Furthermore, males like to dig shallow depressions in the sand prior to spawning, which is less likely to occur if gravel is used.
In the aquarium, live plants are a viable option. Peacocks do not eat plants, unlike other Lake Malawi cichlids, but they nonetheless have a tendency to dig and uproot them. All plants should be fastened or secured. Java Fern should be tied to drift wood or rocks with black string or fishing line. Other plants should be potted (when possible) and wedged in between rocks. Even though Peacocks have adapted to a dimly lit environment in the wild, they readily adjust to the higher light levels required for the growth of aquatic plants.
The water in Lake Malawi is quite alkaline, although minor differences from location to location have been observed. The average surface temperature ranges from 74 - 82˚F (23 - 28˚C), depending upon the time of year and location (Konings 2001). Being a large body of water set in the tropics, its fauna is never subjected to rapid changes in temperature or chemistry. In the aquarium, efforts should be made to create as consistent an environment as possible. The temperature of the water should be stable, without sudden fluctuations. A reliable heater will help maintain a fairly constant water temperature. A long-standing rule of thumb for getting the appropriate size heater is to select a heater with a rated wattage equivalent to 3 watts per gallon of aquarium water.
In addition to a stable water temperature, attention must also be paid to the water chemistry. The first step to creating stable water chemistry is to harden the water. GH and KH levels
In the lake, males are solitary and territorial. Males' territories are usually 0.5 m in diameter and typically center around a crevice or a rocky overhang, which functions for rear cover and offers escape. In contrast, females live solitary or in small groups and usually linger near the males' territory (Spreinat 1995). Keeping this in mind and relying on aquarists' experiences over the last three decades, it is generally recommended to keep Peacocks in a ratio of one male to two or three females.
Breeding Peacocks in the aquarium is generally not very difficult. Courting rituals are both vigorous and prolonged, making them very exciting to watch. In the lake, males typically display at the entrance of a cave or grotto, where they have dug a shallow spot in the sand (Staeck 1981). They will display with their fins erect and oftentimes their thin, lateral bars darken. Courting males make darting, flashing movements in an effort to gain the female's attention. Once a male has attracted a consenting female, he will lead her to this shallow nest. They will make several passes across the nest in the classic T-position before the female finally drops a few eggs. Just as the female reaches to pick them up, the male fertilizes the eggs. The two will repeat this process dozens of times, and it seems they only stop when the female eventually loses interest. Once spawning is complete, the female will incubate the eggs in her buccal cavity for a period of 21 to 28 days. When the fry are developed enough to swim and forage on their own, she will release them. In the wild, a mother will care for her young for the first week or more but this is only rarely observed in the aquarium. Depending upon the size of the female, spawns of most adult Aulonocara species number between 12 and 50 eggs and newly released fry measure roughly 10 mm. Most aquarists prefer to keep their aquariums in the range of 78 - 82˚F (26 - 28˚C) on the grounds that spawning occurs more readily when these fish are kept in warmer water (Loiselle 1988). Warmer temperatures will also speed the development of embryos within the mother's mouth, effectively reducing the holding time and thereby decreasing the duration of time between spawns.
Aulonocara species are known for their tendency to cross-hybridize; consequently, many responsible aquarists refrain from keeping more than one breeding group in the same aquarium. It is possible; however, to keep different species together if these are selected properly (Konings 2002).
Cross-hybridization is obviously not a problem if one plans to keep only Peacock males. The setup would prove a cornucopia of
Peacocks can be housed with a variety of other Lake Malawi cichlids. Many of the gentle, medium-sized haplochromines make excellent tankmates. Various members of the genera Copadichromis, Cyrtocara, Placidochromis, Protomelas, Otopharynx, Nyassachromis, and Sciaenochromis are some of the popular fish which are often housed successfully with Peacocks.
Not all Lake Malawi cichlids make suitable tankmates. Peacocks should not be housed with Mbuna or other boisterous cichlids such as Labeotropheus, Petrotilapia, Metriaclima, or Pseudotropheus species. While it is true that Mbuna and Peacocks both live in the rocky biotopes of Lake Malawi, they infrequently have contact. Peacocks typically reside at a depth of 6 to 40 m; Mbuna on the other hand, are usually found in the upper 5 m of the water column (Spreinat 1995). The reason for this difference is due to dietary differences between the two groups. Mbuna graze the algae growing on the rocks in the lake. The algae require strong light in order to flourish. Peacocks live at depths far too deep for the algae to grow in abundance. It follows therefore that Peacocks and Mbuna are not natural conjoiners.
As you can see, the Peacocks of Lake Malawi are exquisite fish with a remarkable specialization. Their striking colors, ease of care, relative peacefulness with other fish, and their prolific aptitude have made them a mainstay in the hobby. With dozens of color patterns, you're sure to find one that suits your taste. If you have never tried one of the Aulonocara species, I recommend giving them a try. You will quickly discover for yourself why they remain a hobby favorite after more than three decades. □