One group of cichlid fish from South America has develop into well-known to sports activities fishermen throughout the world — the “peacock basses” of the genus Cichla. They have even been launched into Central America (and different tropical our bodies of water) particularly for that reason. And what makes them nice sports activities fish additionally makes them inappropriate for the residence aquarium until you might have suitably giant aquarium area out there and are prepared to just accept the problem of elevating and trying to spawn really giant cichlids.
These fish are on the brief checklist of the world’s largest cichlids, which they share with “Cichlasoma” (Nandopsis) dovii, “C.” (Nandopsis) umbriferum, and that enormous from Lake Tanganyika in Africa, Boulengerochromis microlepis. Despite their imposing grownup dimension and their somewhat restricted dietary preferences — they’re piscivores (fish eaters), though not completely so — juveniles and subadults are nonetheless imported and made out there on the market in pet outlets.
While I admire the magnificence of these fish, I can not suggest them to any however the most devoted (and maybe foolhardy!) of South American cichlid aficionados who can present the area and chow they want. Nevertheless, they’ve been stored efficiently in aquariums, and subsequently deserve protection on this collection.
I’ll accomplish that in two elements, starting first with the taxonomic and systematic standing of these fish, together with unlucky conservation conditions ensuing from the intentional introduction of peacock basses into numerous elements of the tropical world to assist sports activities fishing. If you discover this dry, I apologize — however grasp in there for half two, wherein conduct in the wild and upkeep in the aquarium will probably be coated.
How Many Cichla Species?
Again, we glance to Kullander’s (1986, 1989) latest reconsideration of the genus and 15 nominal species, of which solely two names, Cichla ocellaris and C. temensis, are utilized to Cichla species in the aquarium commerce. These embody C. argus Valenciennes 1834, C. atabapensis Von Humboldt 1834, C. bilineatus Nakashima 1941, C. brasiliensis Schneider 1801, C. intermedia Machado-Allison 1971, C. monoculus (Spix 1831), C. multifasciata (DeCastelnau 1855), C. nigrolineatus Ogilvie 1966, C. ocellaris Bloch and Schneider 1801, C. orinocensis Von Humboldt 1834, C. speciosus (Muller and Troschel 1849), C. temensis Von Humboldt 1834, C. toucounarai (De Castelnau 1855), C. tucunare Heckel 1840, and C. unitaeniatus Magalhaes 1931.
Of these, Kullander has boiled them down to 5 legitimate nominal species — C. intermedia, C. monoculus (synonyms C. toucounarai, C. bilineatus), C. ocellaris (synonym C. speciosus), C. orinocensis (synonyms C. argus, C. atabapensis) and C. temensis (synonyms C. brasiliensis, C. tucunare, C. unitaeniatus). But he suggests (Kullander and Nijssen 1989) that additional examine would possibly increase this checklist to 11 legitimate species. Part of the confusion outcomes from loss of the authentic holotypes — the specimens used for classification — as a consequence of World War II bombings of German museums, and/or lack of locational information.
For aquarists, the checklist of anticipated species contains C. monoculus from Peru (probably Ecuador, Bolivia and western Brazil, however these could also be but undescribed), C. orinocensis from Venezuela and Colombia, the true C. ocellaris from the Guyanas, C. temensis from the Brazilian Amazon River (and the Rio Orinoco, Machado-Allison 1973), and C. intermedia, additionally from Venezuela. Of these, C. temensis and all the different Cichla species (all resembling the passion “C. ocellaris“) are most simply distinguished.
With Cichla temensis now we have a comparatively slender cichlid with a lot smaller scales (Kullander 1986) and a particular coloration sample consisting of an total grey-black physique punctuated by three black vertical bars on the flanks and overlaid with gentle gold spots, at the least as juveniles and subadults (as much as 6 to eight inches). Recent pictures in Glaser and Glaser (1996) recommend that vast grownup C. temensis may very well lose the recognizing. However, I’ve seen some freshly wild-caught (hook-and-line) Venezuelan C. temensis, taken together with enormous C. orinocensis from the similar location, that almost all positively confirmed the attribute recognizing sample and have been simply recognized. The American aquarist Jeff Cardwell (private communication) has likewise taken each C. temensis and C. monoculus collectively in the Brazilian Rio Negro.
Cichla ocellaris and C. monoculus are most related to one another and, significantly as juveniles, share related coloration — principally three partial black vertical bars (or spots) on a brassy physique coloration. Adult C. monoculus, in keeping with Kullander (1986), have wider and longer bars that reach from the level of dorsal fin insertion downward, in distinction to the look of these of C. ocellaris.
According to Machado-Allison (1971), in grownup C. orinocensis three giant ocelli (eye spots) exchange the three vertical bars alongside the center of the sides, whereas C. intermedia (named as such as a result of it’s intermediate in coloration sample between C. temensis and C. orinocensis) has quite a few (greater than three) brief bars. (All Cichla species sport a particular ocellus simply above the center of the base of the tail fin.)
However, identification primarily based on coloration sample shouldn’t be that straightforward or dependable. Complicating this simplistic image are the dramatic variations of coloration that accompany the widespread distributions of all of these species (i.e., see Kullander 1986 relating to C. monoculus). Not solely is the base coloration variable (olive inexperienced to orange to yellow), however the darkness of the bars and the extent of recognizing on the again differs from inhabitants to inhabitants. I refer you to any of the following image assets — Axelrod (1993, although I dispute some of the identifications), Stawikowsi and Werner (1988), and, most just lately and most significantly, Glaser and Glaser (1996) — for a photographic stroll by means of the potentialities.
Actually, the most astonishing catalog of populational variations seems in Schomburgk’s 1843 treatise on the fishes of Guyana. He acknowledges and figures (all hand-coloured prints!) no fewer than 4 “species”‘ of “Cychla,” as he calls them. Interestingly, he lumps the 4 pike cichlids (Crenicichla sp.) he catalogs from Guyana in his genus “Cychla.” Indeed, a number of described “species” of Cichla (e.g., chacoensis Holmberg 1891, conibus De Castelnau 1855, labrina De Spix 1831, niederleini Holmberg 1891) have since been accurately reclassified in the genus Crenicichla (Ufermann et al 1987).
Moreover, all Cichla species expertise profound adjustments in coloration as they develop to maturity. For instance, Kullander and Nijssen (1989) describe these adjustments for C. ocellaris. Young fish as much as about 2¼ inches sport three darkish spots on their flanks (along with the tail fin ocellus) that then increase to develop into partial vertical bars. At about 2½ to three inches, spots develop on the again and sides, solely to vanish at about 3½ to four inches. Specimens of 6 1/three inches in size or longer develop an ocellated spot close to the high in bar three (closest to tail). The coloration sample continues to alter as the fish continues to develop, and adjustments nonetheless additional in reproductively lively (courting and breeding) people.
Lowe-McConnell (1969) additionally famous developmental adjustments in coloration on this species. And Schroder and Zaret (1979) have described intimately the development of patterns from two-week outdated larvae to mature adults. Similar coloration adjustments have been famous and described for C. monoculus (Kullander 1986). Glaser and Glaser (1996) embody pictures of each juveniles and adults for a quantity of populations and species of Cichla, and the developmental variations are sometimes astonishing.
Schroder and Zaret (1979) imagine that the preliminary “striped” sample facilitates education conduct, and that when the fry disperse (11 to 15 weeks outdated) to start a solitary existence in the vegetation alongside the shore, the barred juvenile sample develops. Because the kids at this level of their lives are comparatively stationary, not often venturing out quite a lot of ft from the aquatic vegetation, the barred sample serves them effectively as camouflage. At this level, the tail fin ocellus develops together with a number of (tender) dorsal fin ocelli.
Schroder and Zaret (1979) have described the dorsal fin erection show that small C. ocellaris reply with to the method of bigger, probably harmful C. ocellaris. They imagine that the conduct and the ocelli facilitate recognition of others inside the similar species, and prevents cannabalism of juveniles by grownup C. ocellaris. The ocellus on the base of the tail fin apparently has one other operate, which we are going to evaluate beneath.
We can definitely see the distinction — as the aquarium commerce has achieved for years — between C. temensis and the relaxation of the species. The finest we are able to hope to do with the others, assuming affordable export data (e.g., Peru versus Brazil versus Venezuela versus Guyana), is to assign a tentative identification primarily based on website of possible seize.
We would then seek advice from the specimens as C. sp. affin. monoculus or C. cf. monoculus in the event that they got here from Peru, with the “species affinis” or “cf.” designation suggesting the possible somewhat than absolute id of our fish. Even this can be going a bit far. Various species have been imported for aquaculture even inside South America (e.g., C. temensis from Brazil imported into Guyana, Lowe-McConnell 1969) and probably (most likely) have been launched into open water. Well, we are able to merely name them “peacock bass” as the sports activities fishermen do, or “tucunare” (Brazil) or “lukanani” (Peru) or “pavon” (Venezuela) as the native fishermen do!
Evolutionary Status of Peacock Basses
Another attention-grabbing side of the biology of the peacock basses is that they appear distinctive in look, maybe even “out of place” to the informal fish observer, relative to the different South American cichlids. In reality, a minimum of the American ichthyologist C. Tate Regan (1906) positioned the genus Cichla close to the start line for the evolutionary radiation of the South American Cichlidae, with Cichla splitting off first from the ancestral New World cichlid, then the Chaetobranchus/Chaetobranchopsis lineage, and at last the Acara lineage, believed by Regan (1906) to be the “starting point for the evolution of the genera inhabiting South America.”
And later, Regan (1920) intimated a doable hyperlink between Cichla and the haplochromine cichlids of Africa primarily based on the construction of the ventral floor of the neurocranium (cranium) that gives a “movable joint” for the higher pharyngeal jaw (often called the pharyngeal apophysis). Indeed, Stiassny (1982) confirmed the “Haplochromis”-type construction of the Cichla pharyngeal apophysis, however interprets this shared construction otherwise than Regan (see beneath).
Kullander (1983), like Regan, regarded Cichla as a primitive genus amongst extra superior cichlids. Liem (1973), too, regarded the “primitive” state of the pharyngeal jaw equipment in Cichla as proof for this cichlid’s total evolutionary primitiveness.
Stiassny, nonetheless, has concluded in any other case. Rather than decoding the “primitive” anatomy of Cichla (and the carefully associated genus Crenicichla — pike cichlids) as proof of their base place in cichlid evolution, she means that Cichla (and Crenicichla) are extremely superior cichlids. She develops that argument in a collection of papers (Stiassny 1982, 1987, 1992) that represent an exhaustive comparative anatomical examine of Cichla and numerous different evolutionary key New World and Old World cichlid fish.
In a nutshell, Stiassny argues that Cichla, not like the majority of piscivorous cichlids, swallows its prey complete somewhat than utilizing the pharyngeal jaw equipment to course of the meals. She cites observations by Pellegrin (1903) and Chichoki (1976) that juvenile peacock bass can and do take prey of as much as one-third of their very own size.
And, in specifically preserved Cichla specimens used for examine, fully intact prey fishes are clearly seen of their stomachs. In swallowing prey complete, Cichla (and the pike cichlids, Crenicichla sp., which Stiassny believes is the sister group to Cichla) are not like the relaxation of the South American Cichlidae. Far from being a “primitive” cichlid, peacock bass ought to be thought to be extremely specialised riverine predators which have secondarily acquired a set of seemingly primitive anatomical options that allow them to make use of comparatively giant prey fishes. The time period “atavism,” that means “re-expression of ancestral morphologies,” is used to explain the reappearance of a personality state typical of a distant ancestor (e.g., the ancestor of all cichlids) in a person that basically shouldn’t have it (e.g., a contemporary cichlid).
If Stiassny is right (and I imagine she is; her anatomical analyses are painstakingly detailed), that is another excuse why the peacock bass have attraction for these aquarists preferring giant, predatory aquarium fish. And there’s extra. The peacock basses are some of the most beloved freshwater sports activities fish in the world.
Peacock Bass as Sports Fish
Not surprisingly, peacock bass turned out to be nice sports activities fish for the “rod and reel” set. (The identify peacock bass displays simply that attraction and was coined particularly for fishermen: Cichla sp. are, of course, not bass, and never even remotely associated!)
They develop giant, are colourful, put up an incredible struggle full with robust runs and vigorous leaps, and are nice consuming (McCormick 1949, Schultz 1993). (I hate the style of fish, however have eaten freshly caught C. orinocoense and favored it!) Indeed, Lowe-McConnell (1969) reported Cichla ocellaris to be “one of the best-liked food fishes…caught on hooks (on handlines and by trolling), shot with bow and arrow, trapped as the fish are returning to the main rivers after rains, seined and poisoned from ponds, (and) trapped in coastal trenches.”
They are sometimes encountered in industrial fish markets of the higher Amazon, Orinoco and Guyana rivers (Lowe-McConnell 1984). In reality, it has been reported that catches of Cichla ocellaris close to Manaus, Brazil, have declined markedly as a consequence of overexploitation as a meals fish (Lowe-McConnell 1984).
This could be effective if the end result was merely that avid sports activities fishermen with giant disposable incomes took journeys to South America for the specific objective of catching the wonderful peacock bass (and catfishes, of course). And that is the case. I’ve seen a “Peacock Bass Fishing” video on TV (on a fishing present), and it does look enjoyable, have learn multiple account of such journeys in fishing magazines (e.g., Schultz 1993 “Amazon Adventure” in Field & Stream) and have even been on a accumulating journey to the Orinoco drainage that included a number of people who had come alongside principally to fish for peacock bass and that fanged surprise, the vampirous characoid (Hydrolycus scomberoides). They took C. orinocoense, C. intermedia, and C. temensis of somewhat dramatic proportions, all from the similar location.
However, should you don’t have the cash to go to South America, then the subsequent neatest thing is to deliver the fish to you! Regrettably, introduction of the peacock bass as a sports activities fish has occurred all through the tropics, together with Hawaii, Puerto Rico, Central America and, imagine it or not, Florida (Zaret 1980). And, I’m speaking about purposeful introductions by fisheries individuals, not unintended introductions. I’ve earlier than me a report by the Florida Game and Freshwater Fish Commission (Olgivie 1966) that explores the chance and practicality of growth of a peacock bass sports activities fishery in that state.
In 1965, it was proposed, on the foundation of preliminary tradition “experimentation” in Florida, that representatives of Fish and Game be despatched to South America to do subject analysis. Apparently, experimental introductions into South Florida (three ponds) had met with some success (fish overwintered and reproduced), however it was discovered that the founders have been “small” (lower than 5 kilos) and that “bigger” peacock bass have been out there. Reports that “big peacock bass were from Venezuela” despatched our intrepid explorers there to see for themselves, and to deliver again new founders as a result of “to furnish a sports fishery it would be more desirable if the species attained a larger average as well as maximum size.”
One week was spent accumulating and analyzing specimens in south central Venezuela and conferring with an ichthyologist in Caracas. The report (some 62 pages) is an account of that journey, together with the suggestion that “the addition of any or all of these species to Florida waters would be desirable in my opinion” (Olgivie 1966). There is far good fundamental biology and a few attention-grabbing reviews on the “sporting qualities” of the numerous Cichla species, which lures work finest, which put up the finest struggle, and so forth.). It was additionally famous that spawns have been giant (roughly 1000 to 2000 eggs per spawning), which prompt that enormous numbers of fingerlings may very well be produced simply for the sports activities fishery.
At the time of the report (1966) there have been 18 ponds with launched peacock bass in Dade County, Florida. Some expertise in spawning and rearing in aquariums was listed, and hatchery strategies have been being developed. The use of “natives” (for cichlid meals) was additionally famous, with mosquitofish livebearer (Gambusia sp.) and bluegill sunfish cited most.
Interestingly, it’s famous that 53 yearling peacock bass “cleaned out” a one-quarter acre Tilapia pond in Georgia in lower than two weeks. That pond contained giant numbers of Tilapia from ½ to four inches lengthy when the yearling peacocks have been however an inch, however 12 days later there was nothing however ½-inch Tilapia and presumably nonetheless-hungry peacock bass left! In reality, half of the argument for introducing Cichla was to manage different unique launched New and Old World cichlids (Herlong 1996).
In phrases of temperature tolerance, the pond-launched Cichla survived water temperature drops to 55 levels Fahrenheit, however stopped feeding at round 62 levels (in managed research). However, a fishery biologist from the State of Georgia reported that every one of his peacock bass died throughout the 1965-66 winter. I don’t know what occurred to this plan, however maybe the relative thermal intolerance of these fish made their introduction finally unimaginable.
According to the National Biological Service (Herlong 1996) (Web website on nonindigenous fish standing at www.nfrcg.gov/), Cichla are at the moment established in Florida. That similar Web website signifies that Cichla have been additionally launched into Texas in 1978 by the Texas Parks and Wildlife Department, the place they survived and reproduced for a short interval. But by 1992 all fish had succumbed to the comparatively chilly winters. The mission was discontinued in 1986.
However, related introductions into Panama (Lake Gatun) and Hawaii (a number of reservoirs) have been profitable, a lot to the detriment, it will seem, of the native fishery. In Hawaii (Devick 1971, in keeping with Zaret 1977), in the Wahiawa Reservoir, the place peacock bass have been launched in roughly 1967, the quantity of Cichla was estimated to be 40,000 in 1971, a density of virtually 350 fish per hectare. When these fish have been sampled and the guts of 500 specimens have been examined, they contained identifiable fishes, however not one contained different Cichla. Rather, the peacock bass have been feasting on Tilapia that had additionally been launched into the reservoir beforehand. (The hypothetical purpose for this lack of cannibalism will probably be coated in the second half of this text.) Cichla nonetheless stay established in Hawaii (Herlong 1996).
Zaret (1977, Zaret and Paine 1973) has reviewed the standing of the introduction of Cichla into Panama, each in the Chagres River and in Lake Gatun (42,315 hectare floor space). Approximately 100 fingerlings have been launched to the system in 1967 from Colombia. They prospered and rapidly unfold all through the lake basin, and, regardless of the finest efforts of anglers, Cichla had prompted the native extermination of most of the native fishes by 1976.
Hardest hit was the atherinid Melaniris chagresi, the dominant zooplankton predator, which altered the plankton group and the total biotic group. Melaniris is the main meals supply for tarpon that enter the lake and likewise for waterbirds (e.g., terns). Also, decimation of Gambusia nicaraguagensis and the tetras Astyanax ruberrimus and Roeboides guatemalensis, main insectivores, prompted a bloom in insect populations, significantly mosquitoes — vectors of malaria that’s fairly prevalent in the Canal Zone.
Cichla, that are eaten in South American waters by piranha and arapaima (Zaret 1977), had no predators or rivals (different cichlids like “Cichlasoma” maculicauda and “Cichlasoma” panamense are merely dinner for Cichla) in Lake Gatun, save anglers who fished peacock bass intensively. As has confirmed true for Lake Victoria’s cichlids following the introduction of the Nile perch, human tampering with ecosystems isn’t a very good factor. Such appears to be the case with the introduction of the peacock bass to assist sports activities fishing.
In the subsequent installment of our evaluate of the peacock basses, we are going to contemplate the conduct and ecology of these attention-grabbing fish of their native habitat, and relate these observations to the captive upkeep of Cichla species, with an eye fixed to spawning (gulp!). They have been efficiently maintained by a handful of aquarists, and I hope to share these experiences with you to both encourage or discourage, as the case could also be, the captive husbandry of these exceedingly attention-grabbing and delightful behemoths.