Sie sind hier: Startseite Cichlasoma istlanum Cichlasoma istlanum October The large cichlids from Central America are a bit out of fashion currently. That is a sad thing, for hardly any other fish combines in such a perfect matter brillant coloration, personality and interesting behaviour. Of course these fish need large tanks and an equipment that fits their needs, but if these things are given any aquarist will for sure enjoy keeping them. One of the rare species in the hobby is Cichlasoma istlanum the generic position of this species is still an unresolved problem, Cichlasoma is for sure wrong. This splendid species is endemic in the Rio Balsas system in Mexico.
|Published (Last):||22 April 2012|
|PDF File Size:||2.91 Mb|
|ePub File Size:||1.69 Mb|
|Price:||Free* [*Free Regsitration Required]|
Get the best cichlid books at the best price available in the market Classification: Species overview, Central and North America. Photo by Juan Miguel Artigas Azas. Tate Regan to the genus Cichlosoma and placed in his new subgenus Parapetenia. Subgenus that after a year was relegated to a section of Cichlasoma by the same Regan In this genus the fish remained until the big Cichlasoma mess started in once the Swedish ichthyologist Sven Kullander restricted the genus to some South American representatives closely related to the type species, Cichlasoma bimaculatum Kullander, At that point the generic status of istlanum as well as that of around a hundred of other Central American cichlid species placed in that genus was left in the air.
The course of the Balsas mostly consist of rivers of moderate fast to very fast water flows, running on terrains that are rocky but also muddy in bottom composition. This is why the that waters of the lower balsas rivers cannot be expected to be very clear, so that only in the headwaters of smaller affluents is there visibility in the dry season.
However, in my experience clarity is no more than five meters in exceptional cases. During the rainy season Balsas rivers have a strong reddish brown color with no more visibility than perhaps 1 mm, indicating the high contents of fine clay being washed away. It is true that the cichlid is hard to collect but I also found out talking with the people that live in the river course that mojarras cannot be encountered. Snorkeling in the few rivers where this was possible also was unproductive.
Pollution plays its role, and rivers, especially the lower Armeria and Coahuayana systems, are stroked hard by human thoughtlessness. Rio Coahuayana being almost destroyed by the untreated wastes of a huge paper factory north of the city of Colima. It is important to state that, as for other Central American cichlids, Istlanum is just found in parts of the rivers with a maximum altitude of meters above sea level and then just in those waters that are not too cool for them.
Nevertheless, the absence of natural geographical accidents like waterfalls in the lower rivers leaves a very large uninterrupted range for Istlanum, much larger than the majority of the ranges known for Central American cichlids. Cichlids coming from the western part of the range are distinguished from eastern counterparts by the stronger green coloration, mainly in the head area.
The chemistry of the Balsas water is from neutral to alkaline and hardness readings are from hard to very hard. Plant life is found in some rivers in the form of large weeds that the fish use for cover Rio Amacuzac , but mostly no aquatic plants are found in the main courses of the rivers where istlanum lives.
Big boulders are however very usual in the fish range, and those are efficiently used by Istlanum for cover purposes, something that makes them hard to collect with the use of nets. Sandy bottoms are usual in the rivers among the boulders, and muddy areas are to be found everywhere in back water or shallower zones. Fish companions are found in several fish families, the larger being the catfish in the genera Ictalurus, represented by Ictalurus balsanus in the Balsas river and Ictalurus dugesi in the Rio Armeria.
A minnow, Algansea aphanea, is also found in rivers Coahuayana and Armeria and the redhorse sucker Moxostoma austrinum in Rio Armeria. The mullet so called "Fire land trout", Agonostomus monticola, and the tetra Axtyanax fasciatus, are also found in the whole range.
There are also many introduced species, African cichlid representatives like Tilapia rendalli and Oreochromis aureus are found in the whole range, introduced by the Mexican government as a dietary supplement for people in the region. The overall shape of the fish is elongated with a compressed body, a slightly curved profile with a concavity above the eye and a slightly exposed almost straight pre-maxillar pedicel.
Large males develop gibbosities in the frontal area when breeding. Other features are thick lips and a lower jaw a little bit longer than the upper one. Dorsal and anal fins with filaments that extend beyond the middle of the rounded caudal fin, in some cases the dorsal filament beyond the end of it. In normal coloration the fish shows several black blotches along the middle part of the flanks, those more conspicuous being the first, located at the base of the head, one in the middle of the body which is the only one seen in juveniles , and one at the base of the caudal fin, those first and last ocelated with small scales containing blue spots in the middle.
Basic color base is yellowish, lighter in the lower half of the body and much darker to brown in the upper one, the lower part also with a lot of red. Every scale on the flanks show a blue spot larger than those in the ventral area. The head of the fish is dark green in the dorsal area and yellow with an intense green hue in the ventral one.
Fins are translucent showing blue iridescent spots and small red lines that become dots in the first third of the caudal fin. In breeding individuals the red of the lower half of the flanks becomes very intense as well as the dark in the upper part, becoming in males velvety black up to about five black blotches that form a line in the upper part of the flanks and are just clearly visible in dominant individuals.
Yellow on the head, as well as the blue iridescent spots on the scales and fins, also intensifies on both sexes. In this situation they look like a peaceful fish. Breeding activity takes place during the dry season in the slower flowing parts of the rivers near the shores, normally on muddy substrates where the pairs already formed look for a rock where they dig a small cave that fit them at the base of it.
The female then deposits well above five hundred small, almost invisible yellowish eggs on the ceiling of the rock, not thoughtfully cleaned for this purpose; the male then proceeds to fertilize them. Spawns are cared for by the pair, males in the vicinity of the spawning place and females staying close to the eggs and mouthing them most of the time. Females are substituted by the males every once in a while, short time that the female uses to disappear from the spawning area in search of food.
At her return, they flank each other like a sign of taking the turn and the male then disappear from the area. The eggs hatch after two days under aquarium conditions and small wrigglers are placed in the bottom of the cave where they remain until they become free swimming after five days in aquarium.
At this time the female stays closely above the cave just peaking her head to take a close look at her babies every couple of minutes, preventing with her mouth that any dirt may cover them; after that she returns to her position, the male at this time surrounds apparently careless the nest in circles about a meter in radio. I have observed that other cichlids at the sight of the guarding male just change subtly their route to avoid the nest vicinity, any careless fish that comes too close is then chased away by the angry male.
Fry can be watched grazing on any surface, but with predilection for rocks where they seem to find attached algae and small invertebrates. Luck and parents care will tell at this point the future of the little fish. I have observed lucky parents with herds of more than one thousand 2 cm fry, strolling proudly with their babies in the shallows of the river.
I have also observed many pairs of cichlids with small fry just the day before an unexpected storm out of season falls; when the storm has passed not a single pair with fry was observed in the river. Juveniles can be encountered gregariously in the shallows mainly close to overhanging vegetation, where they seem to stay until they become strong enough to swim in the currents and join a group of larger conspecifics.
Conclusion The bigger danger this beautiful cichlid faces is as usual of human origin; introduction of exotic species, both for food or amusing purposes plus the careless pouring of wastes in the river courses, are some acts that pose a risk to all freshwater fish populations in the world.
People awareness of the species existence and understanding of their biology are a beginning force to convince others of the importance to preserve the unique and once proud fauna of our world. References: Adcock, Kent, , "Cichlasoma istlanum: a diamond in the rough", Vol.
Kullander, Lyons, John, , "Fishes from the land of the trucha de tierra caliente". Regan, C. Tate, Ser 7 16 : In: Biologia Centrali Americana. Turner Bruce J, May 27, Cichlid Room Companion.
Name substitutions "Cichlasoma" istlanum refers to Amphilophus istlanus Species treated in this document 1 Amphilophus istlanus.
CICHLASOMA ISTLANUM PDF
JoJole No, create an account now. Oct 17, Messages: Do you already have an account? The bigger danger this beautiful cichlid faces is as usual of human origin; introduction of exotic cichasoma, both for food or amusing purposes plus the careless pouring of wastes in the river courses, are some acts that pose a risk to all freshwater fish populations in the world. I just picked up 4 Red Istlanum last week. Of course these fish need large tanks and an equipment that fits their needs, but if these things are given any aquarist will for sure enjoy keeping them. Suggestion of cichlaso,a common name: Sandy bottoms are usual in the rivers among the boulders, and muddy areas are to be found everywhere in back water or shallower zones.