A striking, deeply compressed (diamond-shaped) schooling fish native to the estuaries and mangroves of West Africa. While juveniles are frequently found in freshwater or light brackish water, adults strictly require high brackish to full marine conditions to survive long-term. They are hyperactive, grow extremely tall, and require massive, open aquariums to accommodate their schooling nature.
At a Glance
Tank Requirements
Water Parameters
Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard Adult
Fully grown Mono Sebae. At this stage, they are often as tall as they are long (up to 10 inches vertically). They must be kept in high brackish or full marine setups with plenty of open swimming space.
Differs in 1 trait from base species
Also known as: Adult Mono Sebae, Marine Moony
Juvenile (Grow-out)
Small juveniles commonly sold in the trade, often erroneously marketed as 'freshwater'. While they tolerate hard freshwater or low brackish water temporarily, they grow rapidly and must be transitioned to highly brackish water.
Differs in 5 traits from base species
Also known as: Baby Mono, Juvenile Moony, Freshwater Mono
Mono Sebae (Brackish) Care Guide Summary
The Mono Sebae (Brackish), scientifically known as Monodactylus sebae, belongs to the Oddballs family group. Adults reach a maximum size of approximately 25 cm and have a compressed body shape with a moderate growth rate. Classified as mostly peaceful, this species primarily occupies the mid-level zone of the aquarium and produces a high level of biological waste.
To thrive, the Mono Sebae (Brackish) requires a brackish required aquarium with a minimum volume of 400 litres and a tank length of at least 150 cm. Water temperature should be maintained between 24°C and 28°C, with a pH range of 7.5–8.5 and a general hardness of 12–30 dGH. A moderate water flow is preferred.
The Mono Sebae (Brackish) is a rewarding species to keep, provided its core environmental needs are met. This species is available in 2 varieties: Standard Adult and Juvenile (Grow-out). Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Mono Sebae (Brackish) Habitat Setup
When setting up an aquarium for the Mono Sebae (Brackish), a moderate water flow best suits their natural preferences. Because this species occupies the mid-level zone, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement. Useful additions include a sand substrate to accommodate their sifting behaviour and smooth gravel or rounded substrate to protect their sensitive barbels. Keepers should note that live planted layouts may be difficult to maintain, as this species tends to uproot or consume vegetation.
Mono Sebae (Brackish) Compatibility Notes
Classified as mostly peaceful, the Mono Sebae (Brackish) is a social species that requires the company of its own kind to thrive. When choosing tankmates, ornamental shrimp are not safe companions, shy or slow-feeding tankmates may be outcompeted at feeding time, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the mid-level zone can help reduce competition and territorial overlap.
Mono Sebae (Brackish) Feeding & Diet Considerations
The Mono Sebae (Brackish) will hunt and eat ornamental shrimp, making it unsuitable for shrimp-focused setups and is an aggressive eater that may prevent timid tankmates from getting enough food — target feeding or simultaneous feeding at opposite ends of the tank can help.
Frequently Asked Questions About Mono Sebae (Brackish)
How big does Mono Sebae (Brackish) get?+
What tank size does Mono Sebae (Brackish) need?+
What water parameters does Mono Sebae (Brackish) need?+
Is Mono Sebae (Brackish) peaceful or aggressive?+
Can Mono Sebae (Brackish) live alone?+
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Similar Species
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Figure 8 Puffer (Brackish)
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Bumblebee Goby (Brackish)
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Green Spotted Puffer (Brackish)
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The Green Spotted Puffer is a highly intelligent but notoriously aggressive fish. While frequently (and incorrectly) sold as a freshwater species, they strictly require brackish water that increases in salinity as they mature, eventually needing high-brackish or full marine conditions as adults. They have beak-like teeth that grow continuously and must be worn down by a diet of hard-shelled foods. Best kept entirely alone.
White Cloud Mountain Minnow
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