Geophagus Megasema: Ultimate Care Guide

Geophagus Megasema is a sand-sifting Cichlid species endemic to Brazil and Bolivia’s upper Rio Madeira basin. 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 wasn’t available for hobbyists until the last couple of decades and is still 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 daily feedings. 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
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 it can be a welcome challenge for those with more experience.

Are Geophagus Megasema easy to care for?

Geophagus Megasema are hardy but sand-sifting species that 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 a substrate, which they will later sift.


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

Water pH

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

Geophagus Megasema Size

Geophagus Megasema usually grows between 6 and 7 inches long.

Food & Diet

Geophagus Megasema is an omnivorous sand-sifting species that 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 the 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 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 the average lifespan is unknown, but likely around 8 to 10 years, which is common for Geophagus Cichlids.

Tank Size

Geophagus Megasema needs a large tank of at least 75 gallons. Choose a tank that is more wide and deep than tall. This species likes to have a large area of the 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 requires a much larger tank.

Tank Setup

As a sand sifter, Geophagus Megasema needs an environment with lots of soft, sandy substrate free of any sharp rocks or pebbles that 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 that don’t need soil to grow.

Java Fern and Anubias are two common Epiphytes that 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 hardscapes to hold the pots in place. This species’ sand-sifting behavior can dislodge not only plants but heavier hardscape elements 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 these fish and the sand in their environment. Pick a filter that 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 that 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 that 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 they have cleaned and prepared. But sometimes, they 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, 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 returning them to 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 form pairs naturally.

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, maintaining tank water with regular changes, and 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 the new plants might have introduced.


Geophagus Megasema is a docile fish that 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 that only preys on much smaller species. The best tank mates are members of their own species. A group of 6 to 8 will lead to better behavior, although you’ll notice the formation of a definite dominance hierarchy. Aside from breeding pairs, smaller groups may lead to smaller and weaker members getting bullied. Good tank mates can include Electric Blue Acara, Keyhole Cichlids, and Severum Cichlids.

Larger Tetras can also be a good match, 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 that are small enough to eat, like Neon Tetras, Rasboras, or Guppies.

Where can I find Geophagus Megasema for sale?

Geophagus Megasema is a rare species that 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.

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