South American cichlids represent a very diverse group of fish that are well represented in the aquarium hobby. They range from the diminutive Ramirezi to hefty Oscars, and their behaviors vary from extremely peaceful to belligerent bordering on murderous.
With species that vary so greatly in body, habitat and behaviors, it is very difficult to generalize, and these fish really need to be discussed on an individual basis.
Some of these cichlids work very well in peaceful community tanks, others will mix well with many of the Central American cichlids, and still others will only really thrive in a single species tank.
Popular South American Cichlid Species
Rams / Butterfly Cichlids
The Blue Ram or Butterfly Cichlid (Microphagus ramirezi) hails from the rivers of Columbia and Venezuela. The dwarf cichlids grow to just 2-3”, with the female generally a little larger than the male.
These fish prefer soft, mildly acidic water, with a pH of 5.5-6.5. They are quite sensitive to water conditions, and to keep them in good health, their tank should be pristine with frequent maintenance and water changes.
Rams pair off for breeding; the best way to ensure a breeding pair is to add several individuals as juveniles and allow them to grow together and pair off naturally.
Typical of most cichlids, when they do pair, they will breed readily in an aquarium (although they may take a few tries before they get it right), and both parents will protect the eggs and fry. The female lays between 20-100 eggs in a clutch.
Blue Rams are very peaceful fish and will mix readily with a variety of other fish. They should not be housed with aggressive fish or anything large enough to mistake them for a snack.
The word Geophagus literally means “earth eater”, and this is an apt description, as these cichlids will take large mouthfuls of sand to sift out food particles. Obviously, a sandy substrate is required for these fish to show their natural behaviors, and most plants will be uprooted in short order.
There are many different Geophagus species which include the Geophagus altifons shown above. They range throughout South America as far south as Uruguay, and a single species also lives in Panama. Depending on the species, they can be found in still waters or swift whitewater rivers.
On average, Geophagus are moderately sized fish around 4-5”, although the largest species can grow to 12”. These fish will thrive and display more sociable behavior when kept in groups.
Geophagus species can be a challenging fish to keep healthy as they tend to be susceptible to bloat.
A key to avoiding bloat is researching the preferred foods of the species you are keeping and providing as natural a diet as possible, taking care to include appropriate roughage. In the wild, these may include crustaceans, fallen fruit, or insects and their larvae.
One of the most common and popular cichlids seen in the aquarium hobby, freshwater angelfish (Pterophyllium scalare) are native to the Amazon River. Spending their time in bulrushes, these fish which are often vertically striped for camouflage should be kept in planted tanks.
A shoaling fish, ideally Angels should be kept in groups of 6-7 in a fairly large tank (60+ gallons) and their body type lends itself to tall tanks. As adults, they can be territorial towards one another, and a larger group will diffuse aggression.
They prefer slightly acidic water with a pH of 6-7 and a temperature around 77°F.
While generally peaceful towards other species, small fish like neons or guppies are likely to be hunted and eaten by Angelfish. They should not be kept with more aggressive species like their Central American cousins.
Angelfish will pair up naturally to spawn, and the female prefers to lay her eggs on the underside of plant leaves.
Considered by many to be the king of the aquarium, Discus (Symphysodon sp) are among the most beautiful and difficult to keep cichlids.
Like Angel fish, Discus possess laterally compressed bodies, and there are a wide variety of different colors and patterns both in nature and in the aquarium hobby through selective breeding. In fact, breeding Discus is a major industry, particularly in parts of Asia.
Native to the Amazon River basin, Discus require pristine water conditions in aquaria, including soft, acidic water (pH 5-7), frequent water changes, and higher temperatures than most tropical fish (80-86°F).
Discus are peaceful fish, but become somewhat territorial when mating. Both parents care for their young, and baby discus actually feed off a particular slime the parents secrete through their skins for the first couple weeks of life.
Adult discus typically grow to 8”, although individuals have been reported as large as 9”. As such, they should be kept in a large tank, and live plants and driftwood are their preferred décor. They can be kept in a species specific tank or a community tank with non-aggressive fish.
Found in well-planted, slow moving water throughout the northern parts of South America, the Festive Cichlid (Mesonauta festivus) goes by several aliases including the Flag Cichlid and Barred Cichlid. The black stripe running from its mouth across the top of its back is characteristic of all varieties.
Festivum grow to 8” in captivity, but are peaceful and shy and can be kept readily in peaceful tanks with similarly sized or smaller fish. They need cover to thrive, whether provided by plants, caves, driftwood, or all of the above.
These are very hardy fish that prefer water in the acidic to neutral range (5.5-7); they aren’t picky about water hardness, and can tolerate temperatures from 77-82°F.
Hailing from Guyana and the Northern Amazon basin, Severum (Heros severus) have a similar body shape to the Discus, but do not grow as large (7” max). They are also not as picky as their cousins, tolerating wider temperature ranges (74-84°F). They prefer soft, slightly acidic water (pH 6-6.5), and are classified as semi-aggressive.
Severum come in multiple color varieties and should be kept in a moderately large tank (55 Gal minimum). They are peaceful tank inhabitants who should be kept with similarly sized fish; much smaller ones are likely to “disappear” occasionally.
Like many cichlids, they prefer lots of cover in the form of rocks or driftwood. They are not plant-friendly as they are likely to dig and uproot plants periodically, especially when spawning.
When breeding, they can become considerably more aggressive and territorial. Severum are picky breeders; you will likely have to raise several individuals together to get a breeding pair. Once paired, they are open breeders who can lay up to 1000 eggs at a time.
If you wanted a dog, but your parents said you could only have a fish instead, then the Oscar (Astronotus ocellatus) might be the fish for you.
Oscars are generally considered the most intelligent of all aquarium fish available; they have a memory, clearly recognize their owners, and can even be trained to perform tricks.
These fish are native to Peru, Ecuador, Colombia, Brazil, and French Guiana, and it’s not uncommon to see them in local markets for sale as food fish.
Typically these fish are sold as small juveniles, and many hobbyists have made the mistake of adding them to a community tank without doing their homework. If there’s one thing Oscars are very good at, it’s growing. They can easily grow to 8” long within a year, and top out closer to 16”. They are messy eaters, and keeping their tank clean is a challenge.
Unlike many South American cichlids, Oscars are not picky on water conditions, tolerating a wide range of pH and hardness conditions. Dechlorinated tap water should be fine.
As large and aggressive fish, they should be kept in 75 gallon or bigger aquaria and do best in single species tanks, although a few other similarly aggressive cichlids can be successfully kept with them, including most Central American cichlids (Convicts, Firemouths, Jack Dempsey, etc). Adding more than one Oscar in a tank is a gamble, and is not recommended in less than a 125 gallon tank.
The Green Terror (Aequidens rivulatus) is a beautiful fish with an overall green-blue metallic sheen. This species lives on the Pacific side of South America, in particular coastal river-mouths in Peru and Ecuador.
Growing to 12” long, this fish often lives up to its name, displaying fierce aggression as large juveniles and adults. Mature Green Terrors develop a pronounced hump on its head composed of fatty tissues.
Green Terrors are hardy fish who aren’t overly picky on water conditions, but care should be taken to keep the water clean. Obviously this breed requires a large tank (100 gallons or more), and prefers rocky cover and a sandy substrate.
If you end up with a breeding pair, their aggression is likely to go to a whole other level, and they will literally terrorize their tank mates; for this reason a pair should have their own tank.
South American Cichlid Summary
South American cichlids are a mixed bag of fish who are intelligent, easy to breed, and make great parents. Several of these species are among the most peaceful cichlids and work well in community tanks; others require more space and are far too aggressive to be kept with others long term.
Many South American cichlids are mainstays in the hobby and have been kept in tanks for well over 100 years.
Most prefer drastically different water conditions from their Central American and African relatives, and some such as the Discus require very specific conditions to thrive making them unsuitable for beginners.
Whether you’re looking for colorful, peaceful fish full of personality to add to your community tank, beautiful showpieces that will make others envious, or large specimens who can be hand fed and taught to do tricks, South American cichlids can fill the bill.