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The spotted demonfish, Satanoperca daemon Heckel, 1840

作者 , 1997. print format
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Lee Newman, 1998

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在這篇文章中被論述的魚種: Satanoperca daemon

(This article was originally published in Cichlid News magazine, Aquatic promotions, Vol. 5. No. 3, July 1996; pp. 19-23. It is here reproduced with the permission of author Lee Newman).

Often as an aquarist keeps and works with cichlids, the focus of his (or her) efforts becomes more and more specialized. Starting with South American cichlids almost two decades ago, my interests have led me to concentrate on "eartheaters", particularly those of the genus Satanoperca. To the best of my knowledge, the genus currently consists of six nominal species: S. jurupari, S. leucosticta, S. pappaterra, plus three species that compose the "spotted demonfish" group, Satanoperca daemon, S. lilith, and S. acuticeps. While the first three species (the so-called juruparoids) are moderately difficult to keep and breed, members of the latter trio pose special challenges to aquarists in terms of acquisition, maintenance, and spawning. Literature on Satanoperca daemon is rare, but enough can be extracted from publications by Loiselle (1980), and Leibel (1992a, b) to formulate a plan for captive husbandry. In this article I review information on basic ecology and general husbandry before relating my own attempts to maintain and breed Satanoperca daemon.

Satanoperca daemon

The two prominent blotches on the flank are the basis for the common name, the spotted demonfish. Photo by Lee Newman.

Satanoperca daemon presently available in the hobby is for the most part exported from "blackwater" habitats of Colombia. Though often received in shipments of S. jurupari, the two species are easily differentiated: S. jurupari has a black blotch restricted to the upper half of the caudal peduncle, whereas in Satanoperca daemon the blotch extends onto the fin and is ringed with a bluish-white collar, forming an ocellus. In addition, Satanoperca daemon has two black blotches on the flank below the lateral line, hence the name "spotted demonfish".

As an eartheater, the lifestyle of Satanoperca daemon is closely associated with its substrate; as such, tanks with expansive bottom areas are advisable. I recommend at least a 4'-long (75 gal) aquarium for several adults (which grow to an average length of 10" in captivity).

As Satanoperca daemon is a blackwater species, comments concerning water chemistry are appropriate. According to Goulding et al. (1988), blackwater habitats usually have pH values of 3.5-5.3 and are extremely soft (usually less than 1 dH). Also characteristic of these habitats are dissolved tannins that give rise to the dark, tea-colored tint of such waters. It has been my experience that Satanoperca daemon prospers if these conditions can be approximated in the aquarium. By using reverse osmosis and adding tannic and humic acids (in the form of peat moss, bog wood, oak leaves, or an analogous commercial preparation), a greatly simplified blackwater habitat can be simulated. What appears to be considerably more important than actual pH and hardness values is water quality. Members of this group seem sensitive to waste-product buildup with Satanoperca daemon being exceedingly so. Poor water conditions that lead to cephalic or neuromast "pitting" in Satanoperca daemon do not affect S. jurupari and S. leucosticta. "Pitting" is usually reversible in its early stages through major improvements in water quality. Large and frequent water changes combined with an effective chemical filter (such as PolyFilter) generally effect a "cure." Unfortunately, the cure causes other problems; the use of PolyFilter effectively removes tannic and humic acids required to simulate blackwater conditions. Therefore its use must be weighed against the cost and effort required for large scale water changes with appropriately conditioned water (softened, acidified i and "blackened"). However, continued exposure or a further decline in water quality can often result in the development of a condition referred to as "neotropical bloat." This is not to suggest that neuromast pitting is a precursor to neotropical bloat; there have been many cases of bloat without any signs of pitting. In my experience neotropical bloat seems to affect one fish - possibly the weakest or most stressed individual - in a population at a time. The progression of symptoms are generally the same in each incidence: a sudden decrease in food intake, complete refusal of food, heavy ventilation, hanging listlessly in the aquarium, and finally, abdominal swelling resulting in death. The time period from onset to conclusion of the sequence can vary from three days to two weeks. Unlike pitting, this form of bloat appears irreversible despite attempts at treatment. The most frequently recommended treatment is naladixic acid, commonly sold as Nalagram, which should be used with great caution; it appears that fish are as stressed by the treatment as by the bloat. Of three individuals to contract neotropical bloat, all were treated as above; unfortunately I was unable to arrest or reverse the condition in any of the cases. In summary, water quality management seems the single most important aspect of maintaining Satanoperca daemon; excellent water quality combined with low pH may best prevent neotropical bloat. Finally, it is important to maintain a temperature of 84-88°

Aquascaping should reflect elements of the biology and ecology of this species. According to Goulding et al. (1988), adult Satanoperca daemon are found along wooded shorelines over sandy beaches. To facilitate their characteristic "sifting" behavior, I use a fine grade of light-brown "filter sand" (such as the type used in pressurized sand filters) as substrate. A layer 1.5- 2.0" deep will be constantly sifted and moved about by fish, hence their common name "eartheaters." Although they seem to spend much of their time in the open, I provide several "tangles" of water-logged wood as cover.

Satanoperca daemon is a relatively passive cichlid (by home aquarium standards), being remarkably indifferent toward heterospecifics, including dwarf species. However, they are generally poor at competing for food when housed with larger, fast-swimming characoids (e.g., Hemiodopsis spp.; Mylossoma spp.). Best choices as tankmates are other cichlids that are not so "substrate-oriented," such as Uaru amphiacanthoides, Pterophyllum spp., and Mesonauta spp.. In my experience Satanoperca daemon does not require dither fish. Nor is it nearly as shy as S. jurupari or S. leucosticta. Given the greater ease with which water quality can be managed without the additional bio-load, I prefer to maintain Satanoperca daemon alone. The only negative result of conspecific aggression when maintained in a single-species aquarium is an occasional torn fin.

Feeding is surely the easiest component of maintaining this otherwise demanding species. As juveniles, they rarely refuse any standard aquarium foods. Flake foods tend to be messy for adults, but larger sinking pellets, "foodsticks," and freeze-dried foods are excellent dietary choices.

Satanoperca daemon
The two prominent blotches on the flanks are the basis for the common name, spotted demonfish.Photo by Lee Newman.

Satanoperca daemon
Digging is involved with both feeding and display activities. Photo by Lee Newman.

Satanoperca daemon
A spawning pit prepared by a courting pair may occupy most of the tank floor. Photo by Lee Newman.

In June 1990 I obtained five Satanoperca daemon which were placed in a 35 gal aquarium with an external trickle filter coupled with a mechanical canister filter powered by a magnetic drive water pump. The prefilter floss layer and the sump of the trickle filter were cleaned weekly; also there was a section in the sump that contained a layer of PolyFilter, which was cleaned weekly and replaced as needed. The pleated cartridge in the mechanical canister filter was replaced every three weeks. Filtration maintenance was combined with two 15% water changes/gravel cleanings per week. The temperature was maintained at 88°F; pH - due to the very soft water in Vancouver - was 4.3. The fish appeared to prosper under these conditions and after eighteen months had grown from an average total length of 2.25" to 6" at which time they were transferred to a 55-gal tank. After moving to a townhouse and building a fish room, I was later able to move the fish to a 180-gal aquarium.

It was not until they were approximately two years old that pair formation and courtship behavior were observed. Frequently, in their spacious accommodations, pairs would form, and, as with most neotropical cichlids, Satanoperca daemon becomes more aggressive during periods of reproductive activity. Such activities led to the retreat of tankmates to the upper corners of the aquarium, but the only damage that resulted was torn fins, the occasional lost scale, and restricted feeding opportunities. After observing a week of courtship, I removed and isolated the pair in a 55-gal tank in anticipation of spawning. Determining the gender of these sexually isomorphic cichlids is not easy. With well-maintained adults, females appear "girthier" in the abdomen and are usually "bigger" though not necessarily longer than males. It has also been my experience that females initiate pit digging and actively court males, who spend more of their effort in expelling other fish from the pit area.

Courtship in Satanoperca daemon is generally "typical," consisting of reciprocal lateral displays, head "twitching," mouth-tugging, and branchiostegal flaring. During courtship and spawning-site preparation an extensive amount of digging is done. Pits are dug to the aquarium floor, exposing large areas of glass with the surrounding sand piled high up the aquarium walls. In my experience courtship and digging persist for several days and can either end quite uneventfully or - as it did on three occasions - terminate in spawning. The first spawning observed failed as both members of the pair turned out to be females, laying eggs about three weeks apart. Subsequently, the "pair" was returned to the "home" aquarium with the hope that true pairs would form. In the second spawning involving a different pair of fish, the male and female fulfilled their respective duties. The female began with several "dry runs" over the (glass) bottom of the pit before depositing 15-18 eggs per pass. The eggs are adhesive, light-grey in color, and ovoid in shape (ca. 1 mm in diameter). After each pass by the female, the male moved in to fertilize the eggs in typical substrate-spawning mode. Egg-deposition lasted for about 1.5 hours, resulting in 150-200 eggs arranged in a circular plaque.

The eggs were not tended as one would expect for primitive, mouth-brooding satanopercoids, but instead were buried under 1.25-1.75" of sand several hours after spawning! This "undergravel incubation" is unique to Satanoperca daemon among satanopercoids captively-spawned to date. After covering the eggs, the female took up station over them, leaning s1ightly to one side and vigorously fanning with one pectoral fin while the male patrolled the spawning territory. In this spawning, the female fanned the clutch for three days before reverting to non-reproductive behavior. The eggs were never uncovered by the adults, leading me to recognize that the spawning had failed. Unfortunately, a third spawning event proceeded and ended exactly as the second. Although courtship and its associated digging persisted for several months after the third pairing, no further spawnings have been observed. The challenge appears to be to find the correct combination of environmental and behavioral parameters required for successful spawning.

The only published account of a successful spawning in Satanoperca daemon (Eckinger, 1987) reports that after spawning, eggs were covered with the substrate for several days, after which wrigglers were moved by the parents to another pit where they were again covered with a layer of substrate. Several days later free-swimming fry were observed above the substrate. There was no mention of mouthbrooding. The author further observed that fry would bury themselves when frightened. His report suggests two areas of major importance with regard to spawning: (1) water chemistry and quality parameters and (2) the type and size of the substrate provided. After several failed spawnings, his aquarium had been completely cleaned and re-set with parameters of 86°F, pH 4.5, and total hardness of 2 dH. Also, gravel (2-8 mm in diameter) was used as a substrate rather than sand.

According to Jeff Cardwell (pers. comm.), juvenile Satanoperca daemon can be collected among the leaf litter in the wild, much like Apistogramma spp. Therefore, on a long shot, I provided a substrate of waterlogged leaves, speculating that Satanoperca daemon might use leaves to cover eggs in the wild. In the aquarium however, leaves were buried during digging activities associated with courtship.

There is no doubt that Satanoperca daemon presents significant husbandry and spawning challenges, but knowledge and skills gained when working with such a species are what make the aquarium hobby (and especially cichlid-keeping) so fascinating. As the reader has no doubt noticed, this article does not end with a successful spawning report. Hopefully, information contained herein will provide a basis for an exchange of ideas and suggestions that will eventually lead to success in spawning this beautiful species.

ADDENDUM: Since submitting this article, I received a phone call from Martha Clark of Detroit, MI with questions about spawning Satanoperca daemon. A short time after our conversation, a pair of her fish spawned. They excavated a pit that exposed the bottom of the tank where they deposited non-adhesive eggs directly on the bare glass and then promptly ignored them. Martha removed the eggs to an incubator where they hatched and became free-swimming a week or so later. The fry readily accepted newly-hatched Artemia as a first meal, but proved sensitive (as are the adults) to water quality. Further mortality was experienced when fry were distributed to other interested hobbyists. Martha's experiences, though again emphasizing the demanding husbandry requirements of Satanoperca daemon, at least demonstrate that the species can be spawned.

A brief note regarding my own fish. The adults reported on above succumbed to "bloat" during reconstruction of my fishroom. Another six individuals were acquired in November 1994 and are now fast approaching an age and size at which I expect courtship and (hopefully) spawning to commence.

References Cited

引語:

Newman, Lee. (七月 19, 1997). "The spotted demonfish, Satanoperca daemon Heckel, 1840". 慈鯛魚室同好網. 檢索 十月 23, 2014, 來自: http://www.cichlidae.com/article.php?id=56.