Redhump Eartheater

Quick Take

• This fish's signature feeding strategy risks choking itself every time it eats, and yet it does so constantly. See the gill damage risk →
• The fertilization ritual of the redhump eartheater is unlike almost anything else in freshwater fish, with the female's mouth playing a central role. Explore the spawning ritual →
• Redhump eartheaters share a rare anatomical feature with saltwater fish that most people would never expect to find in a river cichlid. Discover the throat teeth →
• This cichlid is famously peaceful, though one specific trigger can flip that completely. Learn about spawning aggression →

The redhump eartheater (Geophagus steindachneri) is a fish that eats the substrate or earth at the bottom of riverbeds or aquariums. Their name, Geophagus, means earth eater. They find food by engulfing mouthfuls of gravel and sand and sifting through it.

The leftover substrate is expelled through the gills or mouth. Some species dig through gravel, creating pits for hiding or spawning, while others just inhale the substrate found on the top layer of the riverbed.

Three Amazing Redhump Eartheater Facts

• These fish are omnivores that feed on detritus found under substrate as well as on small invertebrates.
• Males can grow to around 7 inches in length, while females are smaller and only grow to about 5 inches long.
• They get a lot of sand in their gills after sifting through the substrate for food. This gravel can cause gill damage and may make them choke.

Classification and Scientific Name

The redhump eartheater’s scientific name is Geophagus steindachneri, and they belong to the order Cichliformes. This order consists of ray-finned fishes, with over 1700 species and more than 202 genera split between three families.

Members of this order have sexual reproduction and include groups like:

• Cichlids
• Tilapias
• Convict blennies

Redhump eartheaters belong to the family Cichlidae, whose members are distinguished by their remarkable vertebrate evolution.

They are a fascinating family due to their complex ecological interactions and rapid evolution. They also exhibit some of the most unique and elaborate parenting behaviors. These fish also have several mating systems, which include polygynandry and monogamy.

Appearance

The redhump eartheater has a turned-down mouth with a triangular-shaped head. They can reach lengths of around 7 inches in the wild. However, in captivity, they don’t grow as big.

Male redhump eartheaters’ average length can reach up to 7 inches, and females measure about 5 inches.

They are a cream to orange color with metallic blue or green flecks. These flecks are mainly on the back half of their bodies and extend to their caudal peduncle.

Male and female redhump eartheaters differ slightly in appearance; males have metallic green spotting on their backs once they mature and develop a red hump on their heads, hence the name redhump eartheater. In addition, they have orange spots on the corners of their mouths.

Females barely have any green on their backs and don’t have orange patches on the corners of their mouths.

One feature they share with a few saltwater fish, like parrotfish and wrasses, is well-developed teeth located in their throats, along with a regular set in their mouths.

In addition, they have spiny rays on their dorsal, anal, pelvic, and pectoral fins that help deter predators.

Their average size is around 7 inches in length; however, they can reach up to 7.8 inches in the wild and 6 inches in an aquarium.

Behavior

The redhump eartheater is a very passive fish and does well in aquariums with non-cichlid species. However, they shouldn’t be kept with non-predatory South American species smaller than 6 inches or with aggressive fish.

Their temperament is so peaceful that they can be kept in groups of one male and two females. Surprisingly, they can even be kept with another male if the tank is larger than 125 gallons.

However, they can be aggressive towards conspecifics during spawning stages, especially if the tank doesn’t have enough hiding places.

Habitat

Redhump eartheaters originated in South America, mainly in Colombia and Venezuela. Their habitat of preference is forested tributaries, forested streams, and certain types of backwater habitats with sandy substrate and gravel.

Their ecosystems are under threat from habitat degradation, pollution, agriculture, and expanding human settlements, which can negatively impact water quality and habitat availability.

Diet

These fish are omnivores, and in their natural habitats, they feed on detritus found under the substrate and also on small invertebrates. However, in captivity, they can eat a variety of food like:

• Pellets
• Flakes
• Insects
• Krill
• Shrimp
• Worms
• Crustaceans
• Small fish

In an aquarium, they need 2 to 5 pinches of food a day instead of one big meal once a day. Feeding in small quantities throughout the day satisfies their browsing behavior and improves water quality over time.

Predators and Threats

The biggest threat to the redhump eartheater is human interference. In addition, because they live in shallow waters, they are susceptible to predators like birds and other large animals.

However, their decrease in numbers is due to man-made threats. Chemicals from aquaculture operations pollute waters and are lethal to the redhump eartheater.

They are also victims of fishing expeditions, even though they are not usually the target. However, fishermen don’t always throw them back due to their bright and attractive coloring.

Reproduction, Babies, and Lifespan

Redhump eartheaters are sexually mature at around one year of age, or possibly earlier. They breed well in captivity and are substrate spawners and mouth brooders. Males court females by lying close to the substrate, flaring their fins, and extending their mouths and lower jaws while shaking.

In addition, they dig small pits in the gravel where the female deposits her eggs. After the eggs are deposited, the female scoops them up in her mouth and rubs them against the male’s ventral fin to be fertilized. This whole process takes around 60 minutes. Females can lay a relatively small clutch of eggs, typically around 12–15 in young females, though clutches of up to 61 eggs have been recorded.

After fertilization, the female keeps the eggs, and the males leave. The eggs hatch within two days and are independent a week later. The offspring are called fry; in captivity, they can be fed finely crushed brine shrimp (artemia) or flakes.

Lifespan/Longevity

Redhump eartheaters have a long lifespan of about 10 years!

Population

Unfortunately, there are no records on the population size of the redhump eartheater, but they are classified as Least Concern by the IUCN.