Picking the Right Eartheater for your Tank

Author: Radek Bednarczuk

A wide range of eartheaters are available in the hobby, and while some remain relatively small and are not too aggressive, others can grow into giant brutes that will kill anything in their path, so it is imperative to know which one is right for you.

The eartheaters are a highly variable group of South American cichlids. Within it, there are species that barely exceed 10 cm (4 inches), or are even smaller, as well as those measuring almost 30 cm (12 inches) or more. Some of them are peaceful fish, while others can literally terrorize the entire tank. Within this group of cichlids, we can find those that withstand temperatures in the vicinity of 30°C (86°F), while some others periodically require water temperatures not much above 5°C (41°F) for normal development.

Eatheater Basics

The large number of eartheater genera, as well as the variety of species within each genus, can be a source of confusion. However, there are a few basic questions to begin with: What is your fishkeeping experience, how big are your tanks, and what kind of tap water do you have? You must also decide how much time you can devote to your fish. All these considerations are very helpful when it comes to choosing a species.

At this point, you need to follow your head, not your heart. In other words, don’t act on a sudden impulse. It sometimes happens that you spot an eartheater species that creates a lump in your throat and takes your breath away, so you hasten to buy a group of these fish. However, once they have been introduced into your home aquarium, it soon turns out that your chosen fish are too difficult to maintain or simply are incompatible with the other inhabitants of the tank for various reasons. This is why you should try to be cool-headed and approach the purchase with some detachment.

For Beginners

For novice aquarists taking their first tentative steps into the world of cichlids, with limited time to devote to maintenance, and soft to moderately hard tap water, I generally recommend species of the genus Geophagus. These fish are relatively forgiving of some neglect on the part of their keeper, such as irregular water changes, and are very resilient as far as water chemistry is concerned.

Easy Breeders

An additional source of enjoyment is their readiness to breed, which means we can witness their interesting family life. There is a large selection of species, in various colors, patterns, and sizes, to choose from. In short, you can pick and choose to your heart's content. Novelties from this genus regularly appear in the aquarium trade, such as new color variations and new species not yet scientifically described.


A reasonable choice for the beginning of your adventure with this group of fish would be those species that show relatively little aggression (that is, outside the mating season) and grow to about 12 cm (5 inches), for instance Geophagus sp. “red head tapajos,” which is very colorful, has interesting patterning, and is easy to maintain and breed.

Another fish that I might suggest is the undemanding redhump eartheater (and other species that belong to the G. steindachneri group). They are not choosy with regard to either food or physical and chemical water parameters, the only downside being the considerable aggression shown by adult males, for which the only remedy appears to be providing numerous hiding places and a large number of dither fish in the tank.

Yet another species of the genus (that is somewhat larger than the previous one) that I can honestly recommend for the beginner is G. abalios. This very colorful and showy fish is also easy to breed. Another recommended species is G. parnaibae; the blue hue predominates in its coloration. G. taeniopareius has interesting coloring and general appearance (due to its relatively elongated body); its dominant body color is yellow. Another easy species that has very attractive markings on its body and is suitable for the novice eartheater enthusiast is Geophagus sp.“pindare.”

If you happen to have at your disposal a large tank of a few hundred liters, you can try your hand at keeping some even bigger species, those that exceed 20 cm (8 inches) in length, namely G. proximus, G. altifrons, and G. surinamensis. They will provide you with a real feast of colors. A large group of adult, mature fish can look downright dazzling. Unfortunately, if you choose to keep them, a tank of 400 to 500 liters (100 to 130 gallons) is the absolute minimum for a group of six adult specimens.

Another eartheater known to be resistant to disease and relatively undemanding as far as physical and chemical water parameters go is G. brasiliensis. Once again, however, on account of their size (up to 30 cm (11 inches) in length), you will have to provide a large tank with many hiding places.

For the More Experienced Aquarist

For those of you with more fishkeeping experience, there are some moderately difficult eartheater species to choose from. The genus Satanoperca would be suitable here, ideal choices being S. jurupari or S. leucosticta.

Another group of eartheaters that can be recommended for the intermediate-level aquarist (and even some beginners) are those belonging to the genusGuianacara. They are not very troublesome, stay relatively small (some species do not even exceed 10 cm [4 inches] in length), and reproduce readily—in other words, they have all that it takes to appeal to fish hobbyists. You should keep in mind, however, that the adults can be very aggressive at breeding time and will then bully all the other fish in the tank.

For the Expert

If you are a seasoned fishkeeper with much more time and money (to cover the costs of RO water, the fish themselves, and frequent water changes), you can really take the plunge. That is, try your hand at keeping some of the more demanding species, with more stringent requirements when it comes to water quality, diet, and aquarium size.

Demanding Species

In the difficult category, three species that form the so-called "spotted demonfish group" can surely be included, namely Satanoperca daemon, S. lilith, and S. acuticeps.On account of their required water chemistry (very soft and acidic), an RO filter becomes indispensable in their maintenance. The same goes for peat, through which the water should be filtered. The diet of these fish must consist of common vegetable foods, for they often suffer from neotropical bloat.

Another disease that they frequently develop is hole in the head (HITH), which is why optimal physical and chemical conditions, including a very low level of metabolites, are essential in their maintenance. Obviously, this translates into frequent water changes (using water of the same physical and chemical parameters). A hydroponic or denitrifying filter can also serve as a possiblesolution. Another challenge is the necessity to provide really big tanks with numerous hiding places. S. lilith and S. daemon can easily exceed 30 cm (11 inches). S. daemon likes its water quite warm (around 30°C [86°F]) and acidic (pH below 6).

Acarichthys heckelii

Another species that needs very large tanks with many hiding places is Acarichthys heckelii. If you choose to keep them, the water should be warm (to 30°C [86°F]), acidic, and soft, so once again an RO filter is a must. Other representatives of the more demanding eartheater species are members of the genus Biotodoma (which grow to about 12 cm [5 inches]). Water quality is the essential factor in their maintenance; nitrogen compounds should be undetectable with aquarium tests. They are quite timid, so some companion fish will be necessary. Also, all species of the genus often develop HITH.

The Genus Gymnogeophagus

A worthy challenge for the experienced aquarist would be the beautifully colored and relatively small (from 10 cm to about 12 cm [4 to 5 inches]) species of the genus Gymnogeophagus. Their maintenance is made rather difficult by the necessity to lower the temperature for a period of two to three months. This is done to replicate the environment in their natural range—primarily Uruguay, where in winter the temperature can drop to just a few degrees above zero.

Tank Placement

If you happen to live in a climate zone where the winter temperatures range from 5° to about 12°C (41° to 54°F), you can try keeping these eartheaters in a pond. Otherwise, you need to set up another tank, for instance in a shed or cellar, where the temperature would remain at the level required for the species in question during these few months. Outside the wintering period, too, Gymnogeophagus are kept in cooler water than the majority of eartheater species: 20° to 22°C (68° to 72°F) on average.

Pick the Right Eartheater for You

I hope that this article will help you, at least in some way, make your choice from among the many species of eartheaters. I am an enthusiast of these fish, and like any fanatic, I would like to have them all in my tanks. Unfortunately, I am faced with some difficult choices here, for in making new purchases, I must consider the fish I already possess. Unless, of course, I decide to set up yet another tank!