Genus, Cichlasoma Swainson, – American cichlids. Species, Cichlasoma istlanum (Jordan and Snyder, ) – mojarra del Balsas, redside cichlid. Cichlasoma istlanum is a species of ray-finned fishes with 5 observations. I just picked up 4 Red Istlanum last week. 3 of them from COA and 1 male from Rapps. The ones from COA are Gmfishnuts original strain and.

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Pam Chin has been replying to cichlid questions for over twenty years. Highly respected and experienced aquarist, Pam has visited cichlid habitats around the world, and bred in her’s and her husband Gary fish house hundreds of cichlid species. Besides her job, she still devotes time to help any person with a cichlid question! Articles for sale Beautifully formatted and wonderfully illustrated PDF articles about all matters relative to cichlids. E-books istlanuj sale PDF copies of popular cichlid books offered for sale at the best price.

Trade section The master list of cichlid offers ordered by area and species name. Photo by Juan Miguel Artigas Azas. Ruling the underwater environment of the Mexican largest Pacific drainage, the Balsas river system, lives as the solely native representative of the cichlid family a beautiful fish of magnificent colors and interesting habits, ‘Cichlasoma’ istlanum.

Istlanum, First placed in the cichlid genus Heros by it’s describers, was later moved by the ichthyologist C. 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 Cicchlasoma 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 cichlsaoma 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.

It has been suggested then that Istlanum according to it’s feeding technics could be considered part of the genus Nandopsis Gill Konings,but recently Dr. So, it seems ‘Cichlasoma’ Istlanum will have to wait for a genus of his own istlabum more study istlahum carried on about the former Middle American representatives of the genus Cichlasoma.

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. Wheteher this prevailed in the past I wouldn’t know, since it is a fact that land deforestation has contributed its deal to this situation.

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. The range of ‘Cichlasoma’ istlanum is not restricted to the Balsas river system, but it also extends to smaller systems west to Sierra Coloma at N.

This mountain range acts as a barrier for istlanum distribution, the other side of which makes the beginning of that of the istlanum sibling species ‘Cichlasoma’ beani Jordan I have done extensive collecting with casting nets in rivers in the Colima state, but wasn’t cichllasoma to catch a single specimen. 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 iwtlanum. 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 istlamum 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.

This fact limits the istlanum habitat to a fraction of it’s potential range, as Balsas tributaries courses are found in a good part above this altitudes. Nevertheless, the absence of natural geographical accidents like waterfalls in the lower rivers leaves a very large uninterrupted cicblasoma for Istlanum, much larger than the majority of the ranges known for Central American cichlids.


We have to add that ‘Cichlasoma’ istlanum is the only natural cichlid in the Balsas, and so it has no competition for habitat. The extensive range of ‘Cichlasoma’ istlanum has given origin to several geographic color forms of the fish, the one shown in the photographs I have to admit being not the most colorful variant but coming from one of the few areas I know where the water is clear enough to take underwater photographs, Rio Papagallo in the Guerrero State N.

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 istlaanum 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 Amacuzacbut 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.

Cichlasoma istlanum

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.

Also central America is represented in upper Rio Amacuzac by the recent introduction by hobbyists of Archocentrus nigrofasciatus that has bloomed, becoming a possible threat to ‘Cichlasoma’ istlanum populations.

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 cicylasoma in the cichlazoma 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 juvenilesand 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. My observations on cichlaoma istlanum show that they are usually a shy gregarious fish moving close to the river floor in small groups among the banks, stopping once in a while to shovel their mouths several times in the sandy or muddy bottoms to get a mouthful of substrate that they filter in search for any edible matter, proceeding afterwards to spit the rest back to the substrate.


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 cichlaso,a, 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 istlankm then disappear from the cichlaso,a. 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.

Cichlasoma istlanum : fisheries

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.

Wrigglers become free swimming and at this point they abandon the nest for good, both parents staying close to guide them through the shallow and quiet waters of the river to graze for food, mainly the male showing the route with the typical ‘Cichlasoma’ spasmodic movements of his fins and the female staying close to the heart of the fry cloud. 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. 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 cichllasoma that pose a risk to all freshwater fish populations in the world.

People awareness of the species existence and understanding of their biology are cuchlasoma beginning force to convince others of the importance to preserve the unique and once proud fauna of our world.

Artigas Azas, Juan Miguel. Retrieved on December 31,from: Home Welcome to the cichlidae information center!! Catalog Cichlids Ecoregions Match the id. Library Bibliography Magazines Reviews. Documents Articles Breeding tanks Interviews. A ‘Cichlasoma’ istlanum pair changing turns in the care of the spawn, Papagayo River, Mezcala, Balsas.