Betta Macrostoma

The Betta Macrostoma, scientifically known as Betta macrostoma, belongs to the Anabantoids family group. Adults reach a maximum size of approximately 11 cm and have a fusiform body shape with a moderate growth rate. Classified as semi-aggressive, this species primarily occupies the surface, mid-level, and bottom zones of the aquarium and produces a medium level of biological waste.

To thrive, the Betta Macrostoma requires a freshwater only aquarium with a minimum volume of 80 litres and a tank length of at least 60 cm. Water temperature should be maintained between 20°C and 25°C, with a pH range of 4–6 and a general hardness of 0–5 dGH. A low water flow is preferred.

Due to its specialist needs, the Betta Macrostoma is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Male and Female. 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.

When setting up an aquarium for the Betta Macrostoma, a low water flow best suits their natural preferences. Because this species occupies the surface, mid-level, and bottom zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline, open swimming space in the centre of the tank for free movement, and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include driftwood, which can serve as both a hiding place and a dietary supplement, leaf litter or blackwater tannins to replicate their natural soft-water habitat, and floating plants to diffuse overhead light and create shaded areas. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.

Classified as semi-aggressive, the Betta Macrostoma is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, any fish small enough to fit in its mouth will likely be eaten, ornamental shrimp are not safe companions, conspecific aggression can be intense, especially in smaller tanks, territorial behaviour may cause issues if hiding spots or floor space are limited, and boisterous or fast-moving tankmates may cause this species undue stress. Selecting tankmates that favour different water layers from the surface, mid-level, and bottom zones can help reduce competition and territorial overlap.

Betta Macrostoma is best for a fishkeeper who wants a species that can settle into a calmer community setup and can provide someone who understands its individual space requirements. It makes the most sense for a hobbyist who will actually build around its needs, especially leaf litter/blackwater.

The most common mistake is buying Betta Macrostoma for looks first and only later discovering how its adult size, behavior, or bioload changes the whole tank plan. Another frequent problem is forcing it into an over-busy community when it would do better with more room or more deliberate tankmate choices.

The Betta Macrostoma is a predatory species that will readily consume small fish, so nano or bite-sized tankmates should be avoided and will hunt and eat ornamental shrimp, making it unsuitable for shrimp-focused setups.