Geophagus Megasema: Ultimate Care Guide

Geophagus Megasema is a sand sifting Cichlid species endemic to the upper rio Madeira basin in Brazil, and Bolivia. They’re best kept in soft and slightly acidic water to enhance coloration and health. Besides having bright and impressive coloration given proper conditions, Geophagus Megasema features a large dark spot on either side of its body. This fish hasn’t been available for hobbyists until the last couple of decades, and is still rather rare. In nature, it sifts sand for small insects and detritus. In a home aquarium it’s best to feed only small foods with repeated feedings through the day. If you’re planning on adding this unusual species to your collection, be aware that it has some special care needs. We’ve assembled this guide to tell you everything needed to have years of success with Geophagus Megasema!

Geophagus Megasema Care

Geophagus Megasema is an uncommon fish in home aquariums and they have special dietary needs. This isn’t the best fish for new aquarium hobbyists, but can be a welcome challenge for those with more experience.

Are Geophagus Megasema easy to care for?

Geophagus Megasema are hardy but are a sand sifting species which need very small foods and clean tank water. This fish does best with 3 to 4 smaller feeding per day. They won’t immediately eat all food added to their tanks, but will allow most to fall onto substrate which they will later sift.

Geophagus Megasema
Geophagus Megasema


Geophagus Megasema can tolerate water temperatures between 72° and 86° F.

Water pH

Geophagus Megasema wants water that is slightly acidic to mostly neutral, between 5.5 and 7.5 pH.

Geophagus Megasema Size

Geophagus Megasema usually grows to between 6 and 7 inches long.

Food & Diet

Geophagus Megasema is an omnivorous sand sifting species which can be fed a range of small live and prepared foods. In nature, they mostly feed by taking in mouthfuls of sand which they sift for edible items.  The base of their diet needs to have a high percentage of vegetable matter such as Spirulina. All foods given should be small, as even adults cannot eat larger food items. It’s best to feed 3 or 4 small meals a day because this species doesn’t eat large quantities at one time, preferring to slowly graze and sift through sand over the course of a day. They’ll likely come up for some food when it’s added to their tank, but will spend most of the day sifting through sandy substrate near the tank’s bottom. It’s a good idea to have an auto feeder with can be set to meet this species’ frequent feeding schedule. Live and frozen foods can be provided but only in smaller quantities: the largest portion of this species’ diet should consist of vegetable matter.


Geophagus Megasema is an uncommon fish species in aquariums and average lifespan is unknown, but likely around 8 to 10 years, which is common for Geophagus Cichlids.

Tank Size

Geophagus Megasema needs a large tanks of at least 75 gallons. Choose a tank which is more wide and deep than tall. This species likes to have a large area of substrate for grazing, as grazing substrate is how it spends a large percentage of its time. Geophagus Megasema likes to be kept in groups of 6 to 8. While a large group is ideal, it will also require a much larger tank.

Tank Setup

As a sand sifter, Geophagus Megasema needs an environment with lots of soft, sandy substrate which is free of any sharp rocks or pebbles which might injure them. Adding rocks and bogwood can help mimic their natural environment. Like many sand sifting species, this fish is not suited for planted tanks. Their constant grazing behavior can move and dislodge rooted plants. Geophagus Megasema won’t eat plants so they can be safe for most plants which don’t need soil to grow. Java Fern and Anubias are two common Epiphytes which can be anchored to rocks and wood. Floating plants can be good options as well. If you must have rooted plants they should be potted in suitable growing soil, with rocks and other hardscape to hold the pots in place. This species’ sand sifting behavior can dislodge not only plants, but heavier elements of hardscape as well. Always place rocks, wood and other hardscape items in the tank before adding sand. This gives them stability so they can’t be dislodged when Geophagus Megasema rearranges substrate in the aquarium.

Filtration will need extra attention. While Geophagus Megasema isn’t a particularly messy fish, their eating and grazing habits can kick debris into the water column. The filtration system you choose shouldn’t produce strong water currents. Filter output should be directed through a spreader which prevents heavy inflows from disturbing this fish and the sand in their environment. Pick a filter which can turn over 4 to 5 times the volume of your tank in an hour. For a 75 gallon aquarium, you’ll need a filter which runs at between 300 and 375 GPH (gallons per hour). Canister filters can be a good choice, but take extra care to direct their output through a spreader to break up their stronger flow output.


Geophagus Megasema is a mouthbrooding species which has been successfully bred in home aquariums. There isn’t a known method to trigger spawning aside from feeding a quality diet and performing large weekly water changes. The primary requirement for successful breeding is getting a mated pair. Because it is difficult to determine sex, allowing these fish to pair when young is the best way to ensure having both a male and female.

How do Geophagus Megasema breed?

Geophagus Megasema breed by laying eggs on a smooth rock which they have cleaned and prepared. But sometimes will choose to lay eggs on the aquarium base. The female will lay one or more rows of eggs which the male will then fertilize. After laying and fertilizing around 200 eggs the female will take them into her mouth. Sometimes the male will chase off the female and take over mouthbrooding duties himself, but this is uncommon. Usually the female will care for the eggs and fry while the male guards the surrounding territory. It’s best if this happens in a separate breeding tank as other tank mates can be bullied or attacked during this time.

Fry will become free swimming after 7 to 14 days. The parents will release them long enough to feed before taking them back into their mouths for protection. These fry are easy to feed and can be given powdered dry foods and smaller live foods such as baby brine shrimp, microworms, and vinegar eels.

Geophagus Megasema Male or Female

Determining the sex of Geophagus Megasema is nearly impossible. It’s best to allow a group of juveniles to naturally form pairs.

Geophagus Megasema Disease

Geophagus Megasema are susceptible to common freshwater diseases such as Ich, Velvet, and Hole-in-the-Head disease. The best protection against these conditions is feeding a varied diet, keeping tank water will maintained with regular changes, and by exercising caution with new tank additions. Other fish and plants can introduce parasites and bacteria into an existing aquarium. It’s best to maintain a separate quarantine tank (QT) where potential additions can be observed for 6 to 8 weeks before moving to a community tank. When new plant additions need to be quarantined, you should add a few less valuable fish to the QT. Check these fish for any signs of parasites or diseases which might have been introduced by the new plants.


Geophagus Megasema is a docile fish which won’t predate any but the smallest fish. However, they can become territorial during spawning. Since it is hard to predict when spawning will occur, watch this species for signs of violence against tank mates which can signal the need to move to a private breeding tank.

Geophagus Megasema Tank Mates

Geophagus Megasema is a peaceful fish which only preys on much smaller species. The best tank mates are members of its own species. A group of 6 to 8 will lead to better behavior, although you’ll notice the formation of a definite dominance hierarchy. Smaller groups, aside from breeding pairs, may lead to smaller and weaker members getting bullied. Good tank mates can include Electric Blue Acara, Keyhole Cichlid, and Severum Cichlids. Larger Tetras can be a good match as well, although they need to be members of large schools. Tetras can be aggressive in small numbers and might harass or fin nip Geophagus Megasema. Avoid any aggressive species along with fish which are small enough to eat, like Neon Tetras, Rasboras or Guppies.

Where can I find Geophagus Megasema for sale?

Geophagus Megasema is a somewhat rare species which is only occasionally available from local fish stores. In addition, many online sellers don’t keep a regular stock. Due to the limited availability of this fish, expect to pay between $40 USD and $90 USD per fish, depending on size.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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