Once you have experience keeping more delicate species that are sensitive to nitrogenous wastes, you may want to try the checkerboard cichlids in the Dicrossus genus. If you have naturally soft water, these fish might even breed. First learn a little bit about the taxonomy and distribution of these fish, and then find out how to care for them and breed them in the home aquarium. Checkerboard cichlids are a challenging breeding project that will certainly be an accomplishment if you end up raising some fry.
The South American cichlid genus Dicrossus was first established as a monotypic genus for Dicrossus maculatus by Steindachner in 1875. Later Regan (1905) regarded Dicrossus as a synonym of Crenicara, a view subsequently followed by other authors. In 1990, however, Kullander pointed out that the genus Crenicara comprised a rather heterogeneous assortment of species united only by the presence of a serrated preopercular margin and a similar color pattern. He regarded Dicrossus and Crenicara as distinct enough to be treated as two separate taxa and consequently revalidated Dicrossus. He restricted the name Crenicara to the two deep-bodied species characterized by a greater size and only slight sexual dimorphism of fin shape. Kullander placed the small, slender-bodied, strongly sexually dimorphic species formerly assigned to the genus Crenicara back into the rehabilitated genus Dicrossus.
At present, the genus Dicrossus contains five species:
1. Dicrossus maculatus
2. D. filamentosus
3. D. gladicauda
4. D. foirni
5. D. warzeli
All Dicrossus species are small crenicarine cichlids with the following characteristics:
- Maximum length of 2.4 to 3.5 inches
- Marked sexual dimorphism
- A subterminal, rather narrow mouth
- Two longitudinal series of six or seven alternating squarish or rectangular flank spots (these spots are arranged in a kind of checkerboard pattern, giving rise to the common name of checkerboard cichlids)
Most species are only sporadically imported, and only Dicrossus filamentosus is frequently offered in pet shops. Adult D. filamentosus males can be easily distinguished from the congeneric cichlids, as this is the only species with a bifurcate, lyrate caudal fin, which is distally produced into two filamentous streamers. In adult males of D. gladicauda, the caudal fin is asymmetrical, for only its upper lobe has a filamentous prolongation, while the lower lobe is rounded. In adult D. maculatus males, the shape of the caudal fin is lanceolate, and in the two remaining species, it is oval.
Dicrossus foirni shows a pattern of two series of several small double spots along the middle of its flanks, while the dark markings on the body sides of D. warzeli are arranged in two series of short lines. In the three other Dicrossus species, the shape of the dark flank blotches on the body sides is squarish, rectangular or rounded.
Distribution and Ecological Notes
The distribution of the genus Dicrossus is limited to the Amazon River Basin and parts of the Orinoco drainage in the northern part of South America. Dicrossus foirni occurs in Brazil in the tributaries of the upper and lower Rio Negro. Dicrossus warzeli is distributed in the drainage of the lower Rio Tapajos, and D. gladicauda is known only from the type locality in the drainage of the lower Rio Atabapo in Colombia.
Dicrossus filamentosus has a wide but disjunct distribution, for this species occurs not only in Brazil in the tributaries of the upper and middle Rio Negro, but also in Colombia and Venezuela in several tributaries of the Orinoco. There are several phenotypes of this species that differ in their coloration. In the most attractive variation the lower region of the head is a deep orange.
All checkerboard cichlids are clear- and blackwater species that live in slow-moving, extremely soft water, the pH of which can drop below 5.0. The type locality of Dicrossus gladicauda is, for example, a typical blackwater habitat with clear, acidic and very soft tea-colored water (pH 4.4, electrical conductivity 10 µS/cm, total and temporary hardness less than l degree dH, water temperature 76 degrees Fahrenheit). The fish were collected along the banks of a small rivulet in extremely shallow water (depth less than 1 foot), where they found plenty of shelter either in a layer of dead leaves covering the bottom of the bank sides or among the submerged terrestrial vegetation.
In the Aquarium
Checkerboard cichlids are anything but beginner fish. These dwarf cichlids are suitable for aquarists with experience keeping more demanding species. Dicrossus species are sensitive to dissolved metabolic wastes, which is similar to other dwarf cichlids from blackwater habitats, so Dicrossus should be managed in the same manner. That means that partial water changes are necessary at regular intervals.
Although native to extremely soft waters with a very low pH, all Dicrossus species tolerate harder, less acidic water without any problems in captivity. However, they will not reproduce successfully unless conditions similar to their natural habitats are re-created, for eggs spawned under different conditions usually simply fail to develop normally. Temperatures between 73 to 79 degrees suffice for routine maintenance; raise temperatures to 81 to 84 degrees for breeding.
A pair of checkerboard cichlids has rather modest space requirements and can be housed in a small aquarium with a length of 2 feet and a volume of approximately 10 gallons. But bigger tanks of 3 to 4 feet in length and a width of approximately 2 feet offer some advantages. Sexually active individuals defend small territories – and because this species is inoffensive and social, with highly ritualized intraspecific aggression, it is possible to accommodate more than one breeding pair in such an aquarium. Although the height of the tank is of secondary importance, it should not fall short of 1 foot.
Checkerboard cichlids do best in a well-planted aquarium affording plenty of shelter, which is essential for them. Sand is a substrate that ideally meets the maintenance requirements of these dwarf cichlids. Suitable dither fish are equally important to their well-being. Small characins (e.g., pencilfishes, cardinal tetras or other South American dwarf cichlids of a similar placid temperament, such as smaller Apistogramma species) are excellent choices.
Observations under aquarium conditions revealed checkerboard cichlids to be substrate spawners. Like most other open brooders, these dwarf cichlids place their eggs on a variety of vertical surfaces, but the preferred spawning site is a stout plant leaf or driftwood. The first signs of the forthcoming spawning are courtship behavior and the cleaning of the spawning site, the vicinity of which is defended as mating and breeding territory. In most species, the breeding male and female then replace their checkerboard pattern by a dark lateral band. Dicrossus filamentosus and D. gladicauda differ from the other three congeneric species in being polygynous (i.e., the males defend a territory containing several potential spawning sites). Each of them may serve as the focus of a smaller territory occupied by a female.
Although Dicrossus species spawn in hard and strongly alkaline water, such conditions seem to preclude the natural embryonic development and generally result in egg-eating, which is the female’s response to a clutch that does not develop normally. The females usually lay between 50 and 100 eggs. Once the spawning is completed, the female energetically drives the male from the close proximity of the spawning site. Parental care is exclusively maternal – the female cares for the eggs and larvae alone. The male may indirectly assist by defending the breeding territory against predators.
During maternal brood care, the mother stays almost without interruption above the clutch and fans water over the eggs with strong movements of her pectoral fins. Eggs that do not normally develop are carefully removed from the clutch. At a water temperature of approximately 81 degrees, the larvae hatch about three days after the spawning event. During the next days, the female is likely to move them from the spawning site to several other places. The site is changed at least once a day. The fry usually attempt swimming approximately three days after hatching. That means that they become free-swimming on the sixth or seventh day after spawning. Once they are fully mobile, they are large enough to eat newly hatched nauplii of the brine shrimp Artemia salina for their initial food. Maternal brood care can persist for nearly four weeks in captivity. The females are attentive but often ineffectual guardians. That is the reason why many young fish are lost in a community tank.
With good feeding and careful attention to water quality, the fry can measure approximately 1.6 inches in total length four months after spawning. In most species, they can be sexed at this stage of their development, though it will take two to four months longer before they reach full reproductive maturity. AFI
Wolfgang Staeck has a Ph.D. in biology from the University of Berlin. He is a lifelong cichlid enthusiast specializing in cichlid behavior. He has published the scientific descriptions of more than a dozen new fish species and was the first to report on the behaviors of many cichlid species. He is an educator, lecturer, author and president of the German Cichlid Association.