In April-May 1993, I traveled to the Peruvian Amazon to seek a species of Satanoperca a colleague had collected and photographed from the Rio Yarapa on an earlier trip. This "eartheater" with an emerald green snout, orange lips, bronze body, and elongated ventral fins was unlike any species with which I was familiar. Earlier, Leibel (1988) had also reported a possibly undescribed species of Satanoperca from the same area, providing further motivation for my collecting efforts.
During the first week on the live-a-board vessel, the Delphin, we visited areas where the fish had been sampled previously. However, because the Rio Yarapa was in flood, collecting was very difficult due to increased habitat available to fishes, plus the underwater obstacles that submerged trees presented to our nets, and we failed to find our objective. For the second week we stayed at "Amazon Camp" located on the Rio Momon, a tributary of the Rio Nanay, about 45 minutes by boat from Iquitos. We soon learned with the help of our native guides that many species of cichlids spend the night in very shallow water along the banks of the flooded river. Following their advice, we managed to collect Laetacara thayeri, Crenicara punctulata, and a Satanoperca species at night with a sturdy, long-handled dipnet from the shore directly in front of the camp. According to Kullander (1986), Satanoperca jurupari is the only species of the genus known to occur in Peru, despite slight biotypic variation in color and shape among populations. Of the specimens we caught, 20 individuals (all ca. 60 mm total length) were kept and transported live back to Canada. I estimated that they were at least six months old based on the size of the fish.
The new eartheaters quickly settled in, their initial shyness giving way to anxious, up-front behavior, particularly during feeding, in just a few weeks. Additionally, they did not prove difficult to wean to aquarium foods. Frozen bloodworms, chopped live earthworms, and Cichlid pellets were all eagerly accepted. They have been maintained in relatively large aquaria (200-650 liters) in warm, soft, slightly acidic water (29°C 1°DH; pH 6.5) kept clean with efficient filtration and regular partial water changes. The fish are now 15-18 cm in total length. Of the twenty, eight were passed on to two aquarist friends, and four more were lost during a move in April 1994, leaving me with eight individuals. These eight have been housed together in a 650 liters aquarium maintained as described above for the past several months.
In October, Danny Kent, one of my aquarist friends who had received four of the fish, noticed that one of them was not eating and appeared to be mouthbrooding. Though no spawning had been observed, typical behavior over the last few months had included lateral and frontal displays. After several days the fish resumed feeding and no subsequent activity has been noted. We had assumed to this point that the new fish were biparental, delayed mouthbrooders, but the fact that Danny had not seen any pair-formation, site-preparation or egg deposition suggested otherwise.
Several weeks later I noted increased display activity among the group in my aquarium. At this time the fish were at least two years old and should have been at or near sexual maturity. Two important considerations when attempting to breed any Satanoperca species are that (1) these eartheaters are sexually isomorphic, and (2) they are slow to mature, taking at least two years to become reproductively active. However, several of my eight fish had much fuller abdominal profiles in comparison to their other tankmates. Presumably, these samples represented females and males, respectively. I used this (less than absolutely reliable) technique to determine their sexes, because they had all been reared together for 18 months and the females would under optimal conditions become distended with eggs at the onset of sexual maturity.
About this time, a male (based on a slimmer abdominal profile) had staked out a territory, defending the right half of the tank, which contained a small section of waterlogged wood and a plastic plant. Then the male with branchiostegal-ray flaring, lateral displays, exaggerated swimming, and sifting displays courted a female (with a noticeably fuller abdominal profile). After several days of courtship the female was allowed to remain in the male's territory, spending most of her time under the section of wood. The other six fish were chased by the male - and less infrequently by the female - whenever they strayed from the left half of the aquarium.
After several days of joint territory defense, the female of the pair began to clean a small, horizontal area of the wood in typical Cichlid fashion. It should be noted that prior to this point, neither fish showed any interest in the waterlogged leaves lying on the substrate (provided as moveable spawning platforms). The male, primarily concerned with territory defense, took little part in the cleaning activity. Site preparation lasted several hours during which time the female's spawning tube descended. With the wood cleaned to her satisfaction, the female initiated "dry runs" with the male close by, leaving her only for brief periods to chase away intruders. After several such runs, the female deposited 4-8 light-brown eggs on the wood, swam a short distance from the site while the male fertilized them, then returned and picked them up in her mouth! These fish were immediate mouthbrooders, which was certainly contrary to what we had expected, as all members of the S. jurupari-group are reportedly delayed mouthbrooders. Spawning lasted for approximately ninety minutes, at the end of which time the female had a full mouth of eggs and the male was starting to show signs of disinterest.
In comparison with those of S. leucosticta, the eggs of S. jurupari were larger and fewer in number. Also the spawning site was more typical of that of immediate rather than delayed mouthbrooders, given the pair's choice of a non-moveable rather than a mobile spawning platform. An hour after spawning the male chased the ovigerous female from his territory, playing no further role in parental duties. Even in the relatively spacious confines of the 650 liters tank, the female was constantly harassed by either the territorial male or the other individuals relegated to the left half of the aquarium. Four days after spawning the female was no longer mouthbrooding, evidenced by her renewed interest in food. Proving this was not an isolated, anomalous case of immediate mouthbrooding, a second male soon evicted the original male from his territory and subsequently spawned with two females in the manner described earlier. Consistent with their immediate mouthbrooding behavior, these fish appear to be polygamous. Based on observations of this admittedly limited number of spawnings, the male establishes a territory, solicits a ripe female for spawning, then chases her from the territory and begins courting other ripe females. Following two of the three spawning events, the male was observed to mouthbrood a small number of eggs. However, this behavior lasted for less than eighteen hours postspawning.
None of the above-described spawnings resulted in fry. It seems that either the males are not fully reproductively competent yet or continual harassment of the ovigerous females causes premature termination of the buccal incubation period. Following the last reproductive effort, the brooding female was moved from the home aquarium to a 40 liters incubation tank to conclude the brooding period in relative peace and quiet. During the transfer process she spit out 32 eggs, which were collected and placed in a modified sponge hatchery. The next day, 30 of the artificially incubated eggs had turned white, most likely damaged by handling. However, two were still light brown and presumably fertile. All the eggs were incubated in the hatchery for 42 hours at which time the two fertile eggs were examined with a dissecting microscope. Examination of the embryos revealed a notochord with melanophore pigment and some discernible head development. It appeared that hatching was still a day or two away. In comparison, eggs of S. leucosticta hatch, with assistance from the adults, at 36 hours post-spawning at the same temperature (29° C). It would not be surprising if the time interval from hatching to free-swimming fry proves much longer in S. jurupari than in S. leucosticta.
These observations would seem to suggest that within the genus Satanoperca there might be at least two (and perhaps three) reproductive strategies. Evidence, such as the number and size of the eggs and extended developmental intervals, suggests that in nature the Peruvian form of S. jurupari is a polygamous, immediate mouthbrooder. However, it must be kept in mind that this conclusion applies only to one specific population and may not be representative of others throughout its range. For many years, the Satanoperca "jurupari" in the hobby was in most cases actually S. leucosticta, the earth-eater species with white opercular spotting. The latter species has been spawned frequently by aquarists and is known to be a moveable-platform, biparental, delayed mouthbrooder. However, the popular notion that all Satanoperca are delayed mouthbrooders is quite clearly misleading. Eckinger (1987) reported that S. daemon was a modified substrate-brooder, and according to Winter (1927), S. acuticeps is a typical substrate-spawner. It appears that within the genus Satanoperca , reproductive modality is a plastic characteristic, each species (or population?) having evolved a strategy that works in its particular environment. Regardless, it is an interesting insight into the reproductive biology of Satanoperca.
This article was originally published in "Cichlid News magazine" Aquatic promotions, Vol. 4. No. 2, April 1995; pp. 6-11. It is here reproduced with the permission of author Lee Newman
I wish to thank Jason Hutchison, Alex Saunders, and Danny Kent for help in collecting and transporting the fishes back to Vancouver.
Eckinger, 1987. Nachtzucht von "Geophagus" daemon. DCG-Info 18(7):132-134. Kullander, S.O. 1986. Cichlid fishes of the Amazon River drainage of Peru. Monograph, Swed. Mus. Nat. Hist.
Leibel, W., 1988. Collecting new cichlids the easy way: a reluctant explorer hits paydirt in Peru. Bunt. Bul. (124):2-14. Winter, P. 1927. Zucht und pflege von Geophagus acuticeps Heckel. Woch. Aquar.-Terr. XXIV (no. 9), 1 Marz.