Aequidens tetramerus (Saddle Cichlid)

Aequidens tetramerus

The Aequidens tetramerus (saddle cichlid) is a unique species of fish found in Central and South America, most commonly found in the Amazon basin. While many of its behaviors are typical of fish its size, it also features some interesting and unusual adaptations that set it apart from other species.

The saddle cichlid, or Aequidens tetramerus, (also called the red-bellied cichlid) originates from Central America and South America, specifically in the Amazon and Orinoco river basins.

Looking for an elegant and unique species of freshwater fish? Aequidens tetramerus may be just what you need! Although they are beautiful, these fish are not easy to care for, so it’s important to do your research before deciding if they are right for you and your tank.

Here is the complete species profile of this fish along with all of the information you need to know about caring for saddle cichlids in your home aquarium!

Origin and descriptions

Aequidens tetramerus

Aequidens tetramerus is a large Central American fish species belonging to Aequidens genus. It was originally classified by Günther in 1864. Besides Tetramerus name, it is also called Saddle Jack, Jack-knife Fish, and Four-spot fish. The scientific classification of fish is animalia, which belongs to kingdom animalia under phylum chordata and class actinopterygii. Aequidens tetramerus common name is saddle cichlid which belongs to cichlidae family and order perciformes.

Species profile

Aequidens tetramerus

Known more commonly as saddle cichlids, these fish make great additions to aquariums, large or small. They’re members of a genus that includes at least three other species: Aequidens pulcher, Aequidens rivulatus, and Aequidens ramirezi. All four have rounded bodies and dark gray-to-black coloring with yellow highlights in adulthood.

Saddle cichlids will grow up to 6 inches (16 cm) long when given ample space in a tank and plenty of food.

Unlike some cichlids from Central America, such as firemouths and guapotes, which are best kept alone because they can be aggressive toward each other if crowded into a small tank for an extended period of time, saddle cichlids may be kept in groups; however, they need lots of space (at least 75 gallons per pair), so they don’t injure one another while establishing pecking orders.


Originating from South America, Aequidens tetramerus is a fairly undemanding species that adapts to a variety of water conditions and temperatures. In fact, it is one of the most flexible cichlids in terms of temperature and can survive anywhere between 74 – 84 degrees Fahrenheit. Like other members of its genus, Aequidens tetramerus will spend most of its time in well-planted rocky areas.

Although they don’t necessarily need caves or crevices, they do appreciate having places where they can retreat if needed. Water pH should be kept around 7 but neither alkaline nor acidic conditions seem to bother them too much; a neutral pH of 6.8 is suggested as an ideal range for keeping saddle cichlids happy.

Aequidens tetramerus size

The average size of the Aequidens tetramerus is 162 mm (16 cm or 6 inches)

Aequidens tetramerus tank size

Aequidens tetramerus should be kept in a tank of at least 75 gallons, or larger if possible.

Aequidens tetramerus tank set up

You’ll want to have a 75-gallon tank or more for these fish. They will need places to hide. Rocks, roots, and wood are good to have in your tank. They like low water levels with a little bit of current from an internal filter or powerhead.

For substrate, you should use peat moss instead of sand because sand can get into their mouths and cause problems for them. Plants aren’t as important for them but some can be added to create cover if you prefer that look. If you choose to add plants be careful about having hardier varieties that won’t die off easily under less than ideal conditions.

For lighting, I recommend 2 standard 60-watt bulbs for the overall lengths of your tank. You can also add an optional moonlight bulb or two if you plan on keeping them out later in the evening so they don’t get startled by lights coming on suddenly during feeding time.

Aequidens tetramerus tank mates

The Aequidens tetramerus can be kept with other species of similar size, including Tanganyikan cichlids. Avoid keeping it with aggressive and territorial species.

Some other good tankmates are Altolamprologus, Copadichromis, Julidochromis, Cyprichromis, and most Pseudotropheus species. Although cichlids need a minimum of 5-10 gallons per specimen, you can keep them in as little as 3 gallons if you choose to only have one or two fish. This fish is best kept in tanks with a sand substrate or a mix of sand and rocks.


Aequidens tetramerus

As a species, Aequidens tetramerus is extremely easy to breed. The saddle cichlids are bubble-nesters, meaning they use an empty shell or pottery-formed object and create a bubble out of air and saliva in which they place their eggs. Their nests are typically found on river rocks or wood chips that have been provided as breeding substrates in captivity.

Once laid, care for newly hatched fry is minimal; it’s best to leave them with both parents until they’re around three weeks old. With proper water conditions, food provisions, and consistency, it’s possible for someone new to fishkeeping to breed these cichlids within a few months, and most other tropical fishkeepers can follow suit within 6–12 months.

In short, even if you’ve never kept a cichlid before, it should be relatively easy to find one at your local pet store or online seller who will sell you some young adults just begging to be spawned.

Finding young adults means being familiar with ideal tank mates and whether or not your desired species requires live food additions like brine shrimp nauplii—but such information is normally readily available online via websites devoted specifically to aquarium keeping.

Are Aequidens tetramerus aggressive or peaceful?

They are peaceful as juveniles but similar to other types of cichlids, saddle cichlids are somewhat aggressive as adults. They do not respond well to aggression and will fight back with force. They will protect their territory and must be kept in tanks that allow for plenty of space.

Aequidens tetramerus care

Aequidens tetramerus

The Aequidens tetramerus, or saddle cichlid, is a fairly easy species to keep. It will do best in a tank of at least 75 gallons with a good amount of current; while they will tolerate some still water, they tend to be more comfortable with some aeration. If you’re keeping them in a planted tank, it is highly recommended that you use an under-gravel filter for optimal growth and health. The substrate should be fine gravel or sand.

What do Aequidens tetramerus eat?

Tetramers, like many other cichlids from South America, are opportunistic feeders and eat a variety of foods. In their natural habitat, they prey on crustaceans, fish eggs, shrimps, tubifex worms, larvae, snails, and insects. They also scavenge fallen dead fish in some instances. Tetramers will accept almost any food offered by aquarists, but vegetable matter such as blanched spinach or peat is recommended for optimal health.

Water parameters

The ideal water should have a pH of 8.2-8.4, kh of 10-20, and gh of 2-25 dH; temperature should be between 25 to 28 degrees Celsius. When kept at different water parameters, male saddle cichlids display a wide range of coloration, including white to black bars with blues, reds, and yellows in between. Aquariums containing only females are always light brown/tan colored, but when several males are added to a group of females they instantly show their true colors and display an immense amount of color variation.

Aequidens tetramerus lifespan

They have a typical lifespan of 15 years. Some individuals may live up to 20 years, but most will die of disease before that.

Parasites and diseases

As far as parasites and diseases are concerned, cichlids are not too bad off. The most common disease found in aquarium fish is Ich or white spot disease. This is a virus that affects nearly all aquarium fish and can be very easily treated with medicated food and salt baths. As far as parasitic infections go, if your tap water is clean, you will have no issues at all keeping a happy colony of Aequidens tetramerus.


Large fish, catfish, and turtles will often prey on saddle cichlids. These predators are easy to avoid if you keep your fish in a large tank. Even so, they make suitable tank mates for large African rift lake cichlids and other large Central American cichlids such as convicts and Jack Dempseys. Large South American cichlids like angelfish, convict cichlids, discus fish, and many others will also work well with these fish.

Do Aequidens tetramerus make good pets?

In many ways, saddle cichlids are a lot like guppies, they prefer to stay in large groups; they’re fairly hardy and easy to keep, and they’re relatively easy to breed. But unlike guppies, saddle cichlids are a bit more aggressive, so you should make sure that any tank mates aren’t small enough for them to swallow.