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The Rio Negro Chocolate Cichlid, Hypselecara coryphaenoides (Heckel, 1840)

By Lee Newman
Originally published in Cichlid News Magazine January 1998
Aquarticles

Prior to 1986 there were many names being applied in the hobby literature to the so-called "chocolate cichlids." For the cichlid keeper, this made identification very difficult as distinctions among species were unclear, a situation that was resolved when Kullander (1986) placed the group in the newly-created genus Hypselecara. The generic name is derived from the Greek word hypselos (meaning "high"), in reference to the steep profiles of these cichlids, and acara, a colloquial word for cichlid. Kullander (1986) recognized only two species ­ Hypselecara temporalis (Gunther 1862) and H. coryphaenoides (Heckel 1840) ­ placing H. goeldii, H. crassa, and H. hellabrunni in the synonymy of the former and H. niger, H. arnoldi, and H. axelrodi in that of the latter.

Hypselecara coryhaenoides breeding pair guarding their fry. (Photo by Lee Newman)

The two species of Hypselecara, as presently defined, are easily differentiated. The overall appearance of H. temporalis is almost "square" due to its steep profile, while H. coryphaenoides is more elongate with a gradually elevated profile. There are also color differences between the species. The form of H. temporalis common in the hobby is a green and red-wine fish with a darker lateral blotch centered below the lateral line; H. coryphaenoides is dark-brown to black with a blotch centered above the lateral line and extending into the base of the soft dorsal fin. Unfortunately, two factors complicate identification efforts. First, markings in H. temporalis tend to be quite variable depending on geographical origin; second, H. coryphaenoides is subject to great changes in color and pattern depending upon "mood." As a helpful guideline, wild H. temporalis are usually collected in Peru, while H. coryphaenoides is most often taken in Brazil.

As H. coryphaenoides is comparatively rare in the trade, the chocolate cichlid most likely to  be encountered is H. temporalis. Nevertheless  H. coryphaenoides does not appear to be rare in the wild; in habitats in which we found the species (described below), it was easily collected. However, despite the presence of other rarely seen (in the trade) cichlid species (i.e., Satanoperca acuticeps) in exports from Manaus (Brazil), H. coryphaenoides was absent. Whether this reflected a seasonal phenomenon or just low demand was not investigated.

In January 1996, the Vancouver Aquarium provided resources for me to participate in a two-week aquarist expedition to the Rio Negro and Rio Branco in Amazonas, Brazil. The trip was set up to support Project Piaba, an ornamental fisheries conservation project, while also allowing participants the freedom to pursue individual interests. Representing the Aquarium, I was expected to assimilate as much about the project as possible; however, all my free time was spent studying and collecting cichlids.

The expedition was based aboard the "Cassiquiari," a spacious, 65-ft boat with ample room for the fifteen participants in the trip. The expedition took us from our starting point in Manaus on the lower Rio Negro upriver to Barcelos, then back down the Rio Negro to the Rio Branco, which allowed us a few days to explore a "whitewater" river. The trip concluded in Manaus with a brief excursion to the "meeting of the waters" where the blackwater Rio Negro flows into the whitewater Rio Amazon, plus an opportunity to visit two tropical fish exporters.

Most aquarists with plans to take fishes back to the U.S. or Canada had target-species in mind. Although I tried to remain flexible ­ as collecting in the field is rarely as predictable as buying fish in an aquarium store ­ I hoped to collect some of the cichlids less frequently seen in the hobby.

A brief stop at a floating hotel along the Rio Cueiras, a blackwater tributary of the lower Rio Negro, provided the first opportunity to collect fish the first night out enroute to Barcelos. The hotel was positioned near a cleared section of the gently sloping riverbank and was floated on large tree trunks. By lying on the perimeter walkway and bending over the edge, I was able to collect with a dipnet from the submerged tree trunks.

Abundant in very shallow water were armored catfish of the genus Ancistrus and palaemonid shrimp, as well as juvenile H. coryphaenoides. Both the catfish and the chocolate cichlids were using small cavities or rotted holes in the well-worn trunks for cover. Within an hour ­ with a dipnet in one hand and a flashlight in the other ­ I managed to collect small samples of both species. The chocolate cichlids I magnanimously distributed among other interested aquarists on the trip. Though I thought H. coryphaenoides would be a good species to take back to Vancouver (the chocolate cichlid usually available there is commercially produced H. temporalis), I figured that there would be other opportunities to collect them before the end of the trip. Unfortunately, this was not to be the case!

Late in the trip during our return to Manaus, we stopped one afternoon on an island in the Rio Negro just south of its confluence with the Rio Branco. For several hours the group busied themselves collecting fishes, angling from the boat, taking photographs, sight-seeing, and bird watching. I opted to snorkel in an effort to observe fishes in their natural habitats. I was able to locate dwarf pike cichlids (Crenicichla regani) and a species of Apistogramma among the partially-submerged terrestrial plant growth along the shore. After a couple of hours of snorkeling, I decided to do some photography. While I was taking pictures, Lee Finley was collecting fishes in a shallow area in a small inlet. When we all assembled on the boat for dinner, Lee generously offered up his catch, and I became the lucky recipient of a dozen small chocolate cichlids!

My twelve juvenile (0.8" TL) H. coryphaenoides survived the trip home and were placed in a 340 litres (90-gal) aquarium along with some of the other cichlids collected on the expedition. The juvenile chocolate cichlids displayed a series of brownish-black vertical bars with a light orange stripe extending from the tip of the snout over the head to the soft portion of the dorsal fin. They immediately accepted all foods offered, including live Artemia sp., frozen bloodworms, live whiteworms, and small presoaked cichlid pellets. At this size, H. coryphaenoides displayed little aggressiveness among them and almost completely ignored heterospecifics.

One problem in maintenance noted early on was a sensitivity to free metal ions, particularly copper. The young chocolate cichlids soon began to develop neuromast "pits" (small eroded areas around the neuromasts). It took several weeks to determine the cause of the pitting before a correlation was found between the problem in the fish and the changing of some copper pipes in our building. The easiest solution was to apply a chelating agent with each water change to bind free copper ions, rendering them less toxic. Fortunately, this worked and the pits healed in about a week.

In the aquarium, chocolate cichlids grew rapidly on a diet of cichlid pellets, chopped earthworms, frozen bloodworms, and frozen Mysis relicta. Interestingly, they were very attentive to events at the surface and eagerly accepted live mealworms and crickets.

An adult Hypselecara coryphaenoides in normal coloration. Fish and Photo by Lee Newman.

As the fish grew, the barred pattern gradually gave way to a more uniform brown ground color with a prominent black lateral blotch. At the same time, they also became increasingly less tolerant of conspecifics, while remaining remarkably indifferent to heterospecifics. It soon became necessary to remove several individuals in an effort to curtail aggression. Even this "solution" was short-lived, as additional individuals again had to be removed to maintain a relatively-peaceful community, eventually leaving only five chocolate cichlids in the 340 litres (90-gal) aquarium. When these individuals reached a length of about 10.0 cm (4") TL, they were moved to a 475 litres (125-gal) aquarium which they shared with seven Satanoperca lilith collected on the same trip. The eartheaters though smaller were completely ignored by the chocolate cichlids, even during feeding. The new tank was equipped with a "plant filter" (Newman, 1997) to maintain a minimum nitrate level; a double sponge filter; and a power filter for back-up and additional mechanical filtration. Water parameters were: pH 6.5; temperature 29° C (84° F); hardness (calcium carbonate) 4.2 mg/1; and nitrate ca. 5.0 mg/1. The substrate was a fine sand used to accommodate sifting behavior typical of S. lilith, while several large pieces of waterlogged wood from a local lake provided cover. Lighting was dim ­ a single 40-watt fluorescent bulb on a timer set for about 12 hours a day.

The group of H. coryphaenoides had been in their new home for several months when some fry of Pelvicachromis taeniatus were placed in a 19 litres (5-gal) tank floated in the larger aquarium (so that an additional heater was not needed for the fry). Surprisingly within a day or so, one of the chocolate cichlids had developed a parental color pattern ­ uniformly dark-brown body with a burnt orange dorsal blaze ­ and taken up station under the floating 19 litres (5-gal) tank. The dorsal blaze intensified each time the guardian fish chased another H. coryphaenoides or S. lilith that ventured too close to the floating tank. It indeed appeared that this single parental chocolate cichlid was prepared to adopt the fry as its own. However, because of the value of the P. taeniatus, it was decided (this was not my call!) that the seemingly eager parent-to-be would not get a chance to have any direct contact with the fry, effectively putting an end to this unplanned experiment. Several weeks later when the fry and the floating aquarium were removed, the chocolate cichlid reverted to non-parental behavior and color pattern.

An adult H. coryphaenoides in breeding coloration (Fish and photo by Lee Newman)

By March 1997, members of my colony of H coryphaenoides had grown to lengths of almost 15 cm (6") TL. During the first week of March it appeared that two of the five remaining fish were "tolerating" each other a bit more than previously. They were almost the same size, and it was difficult to determine the sexes of the two fish. The other three were confined to the left side of the tank while the "pair" spent considerable time together under the right-side section of wood. A dead giveaway (excuse the pun) that the pair had established a territory was finding a third fish D.O.A. on the floor, evidently forced out of the tank through a small gap in the lid. The remaining unpaired H. coryphaenoides also displayed evidence of aggression (e.g., missing scales and ripped fins), but it appeared that they would be tolerated as long as they stayed at the far end of the tank.

A few days later the pair began to dig under the right-side section of wood, excavating through the 3.8 cm (1.5") layer of sand to expose the bottom glass of the aquarium. Requiring a full week to dig, the pit eventually spanned an area of about 60 cm square (two square feet)! During these digging activities, secondary sexual characteristics of the pair became noticeable. The male was a bit larger and had developed a slight nuchal hump, whereas the female was much heavier in the abdomen. There were however no differences in color between the two. During the construction of the pit, the pair spent a lot of time inspecting the undersides of the wood pieces in the territory. A week after the completion of the pit, the breeding tubes of both individuals became visible, the male's being relatively thin and short in comparison to that of the female.

The next day the pair spawned on the back side of a piece of wood nearest the right end of the tank. Because egg-deposition took place out of view, it was impossible to determine the number, size, and color of the eggs. However behaviorally, Hypselecara coryphaenoides spawns in typical fashion for substrate-spawning cichlids: the female began with several dry passes over the site before depositing eggs on subsequent passes with the male moving in at regular intervals to fertilise the eggs. The spawning was completed in 90 minutes after which the female took up station fanning the egg plaque while the male assumed territorial defense. Needless to say, the remaining two chocolate cichlids stayed near the left end of the 1.80 m (6") long aquarium.

H. coryphaenoides defending its territory (Fish and photo by Lee Newman)

Two days post-spawning wrigglers were moved to a hollow in a section of wood toward the center of the tank. The male and female took turns transporting the larvae from the spawning site to this new location. Each time a parent approached with a mouthful of larvae, it would signal the other with a lateral display, upon which the second fish would depart to retrieve additional fry.

I waited for five more days (seven days post-spawning) until I thought the wrigglers would be free-swimming to remove a small portion of the brood to insure the survival of at least some of the fry. The sample was removed from the wood hollow with a clean turkey baster and placed in a 19 litres (5-gal) tank floated in the larger aquarium. The incubation tank was fitted with a sponge filter using a mature sponge from the larger aquarium. The fry ­ still with a significant yolk sac ­ were free-swimming the next day. Between the sample in the incubation tank and the fry left with the parents, I estimated that the total brood size was about 300.

Fry readily accepted live, newly hatched Artemia nauplii as their first feeding. The fry in the brood tank were easily fed, while those still in the large tank had to be fed via a section of rigid airline tubing attached to a syringe. Both groups of fry were fed twice a day and seemed to process their food quickly, necessitating frequent cleaning of the brood tank.

When the sampling of fry was placed in the incubation tank, the male left the female and the remaining brood to tend these "orphans." The male behaved just as the single fish had with the P. taeniatus fry mentioned earlier. After another week or so, the male began spending more time with the female under the right-side section of wood where she was tending the mobile fry. The parents frequently signaled to the bottom-oriented fry with rapid flicking of the pelvic fins. In instances of excessive disturbance, such as during feeding, the color of both the male and female intensified (black body with bright, burnt-orange dorsal blaze) signaling the fry to sit motionless on the bottom. For the most part the fry were kept in the spawning territory with only brief excursions toward the middle of the tank. As regards the other fish in the aquarium, the pair practically ignored S. lilith except when one of the latter ventured too close to the mobile fry; in sharp contrast, both members of the pair regularly traversed half the length of the aquarium to reinforce their dominance over conspecifics. At the end of every day, just before the timer switched off the light, the fry were gathered together under the wood near the spawning site, sitting motionless on the sand bottom, presumably for the night.

The 19 litre (5-gal) floating aquarium was removed in a week after which the pair invested their undivided attention on the fry still in the larger tank. At this time I stopped feeding brine shrimp to the fry; after three weeks there were only twelve left. They apparently survived by feeding on small particles of flakes that were fed to the adults.

Quite suddenly the female began hunting the remaining fry, a sure sign that she was preparing to spawn again. However, the male persisted in defending the fry, leading them to a station on the top side of the wood out of view of the female. Over the next couple of days the female worked in the pit, cleaning the site that had been used for the first spawning. The next sign that a second spawning was imminent was the torn fins and damaged scales of one of the other resident chocolate cichlids. The next day the female was much slimmer and reluctant to leave a site under the wood, while the male, continuing to defend the fry from the first spawning (now numbering only four) patrolled the territory perimeter.

Two days post-spawning, the eggs hatched and larvae were placed in the pit on the bottom glass of the aquarium beside a small piece of wood. Several days later the fry became free-swimming; again, I removed a sample of the brood to rear under safer conditions. Unfortunately, I timed the removal of the fry quite badly. I used a small, fine-mesh net to collect the sample which created significant panic with all the cichlids in the tank, especially the parental chocolate cichlids. The remaining fry were quickly dispersed throughout the aquarium and easily eaten by the other chocolate cichlids and resident S. lilith. The sample that had been removed was placed in a 57 liters (15-gal) rearing tank and started on newly-hatched Artemia. They grew very rapidly and within three weeks were feeding on chopped frozen bloodworms and crushed flakes.

Juvenile H. coryphaenoides

Three weeks later the same pair spawned in the same place for the third time. Having little room to rear additional chocolate cichlid fry, I decided to leave this third spawn in the home aquarium to observe parental behavior and fry survival. A day after the fry became free-swimming, one of the S. lilith got a little too close to the shoaling brood. The male chocolate cichlid attacked the S. lilith and managed to score a bite from the flank of the fleeing demonfish. As the eartheater darted away, a flurry of scales were left in its path. Before returning to the brood, the male H. coryphaenoides enthusiastically devoured the scales as they settled onto the sand.

Despite diligent parental protection, the number of free-swimming fry was quickly reduced by opportunistic predation by the other fishes in the aquarium. At about three weeks postspawning, the female became ripe again and began to eliminate the remaining fry herself from the spawning territory. Based on such observations, it seems that only low fish densities combined with complex shelter would allow for recruitment of juveniles to the community at large.

[Hypselecara coryphaenoides] Juvenile Hypselecara coryphaenoides . Fish and Photo by Lee Newman.

For the hobbyist with one or more large aquariums looking to keep something a little "exotic," the Rio Negro chocolate cichlid, Hypeselecara coryphaenoides, with its complex parental behavior and spectacular color changes, could be just the ticket. It is somewhat demanding to keep in terms of space; they reportedly grow to 20-15 cm. (~8-10") TL under suitable conditions in the aquarium and certainly come by their aggressive reputation honestly (Leibel, 1996). However, a point in their favor is the fact that they do spawn at sizes far less than their eventual maximum. Also, the majority of their aggression is directed toward conspecifics. If one resists the temptation to house more than one pair and a couple of conspecific targets in the same tank, their aggression is moderate at worst.

As many cichlid keepers know, there are several techniques one can employ to secure the safety of large, aggressive cichlids engaged in reproductive activities in less than spacious quarters. However, giving this fish an opportunity to express its natural behaviors under conditions similar to what it would encounter in the wild ( i.e., low conspecific and heterospecific densities and enough space to chase intruders beyond the territorial boundary) allows the hobbyist to observe the very behaviors that make cichlids so interesting and popular. Hypselecara coryphaenoides is easily fed and relatively easy to spawn, and for the aquarist willing to provide a large, heavily-aquascaped aquarium, it can be an interesting addition to a community of South American cichlids.

References Cited

* Kullander, S. O. ; 1986; Cichlid Fishes of the Amazon River Drainage of Peru. Monograph of the Swedish Museum of Natural History.

* Leibel, W. S. ; 1996; Goin' south ­ part 26: Cichlids of the Americas, the Chocolate Cichlids. Aquarium Fish 8(1):62 et seq.

* Newman, L.; 1997; The plant filter: going green with filtration. Aquarium Fish 9(6):34 et seq.

Editor's note: The author Lee Newman works as Curator of Tropical Waters at the Vancouver Public Aquarium. See our article about Lee and Lisa Newman  in Aquarticles' People Section.