Green Sunfish

The Green Sunfish, scientifically known as Lepomis cyanellus, belongs to the Other family group. Adults reach a maximum size of approximately 25 cm and have a compressed body shape with a fast growth rate. Classified as highly aggressive, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a high level of biological waste.

To thrive, the Green Sunfish requires a freshwater only aquarium with a minimum volume of 280 litres and a tank length of at least 120 cm. Water temperature should be maintained between 10°C and 28°C, with a pH range of 6.5–8.5 and a general hardness of 5–25 dGH. A moderate water flow is preferred.

Due to its specialist needs, the Green Sunfish is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Adult (Standard) 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.

When setting up an aquarium for the Green Sunfish, a moderate water flow best suits their natural preferences. Because this species occupies the mid-level and bottom zones, the aquarium layout should prioritise 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 a sand substrate to accommodate their sifting behaviour, smooth gravel or rounded substrate to protect their sensitive barbels, and driftwood, which can serve as both a hiding place and a dietary supplement. Keepers should note that expect substrate disturbance, so lightweight décor should be secured.

Classified as highly aggressive, the Green Sunfish is best housed alone, as they do not tolerate others of their kind in confined spaces. When choosing tankmates, any fish small enough to fit in its mouth will likely be eaten and territorial behaviour may cause issues if hiding spots or floor space are limited. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.

Green Sunfish is best for a fishkeeper who expects a species with attitude and plans the tank around that behavior 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 sand.

The most common mistake is treating Green Sunfish like any other community fish and skipping the soft sand it needs to forage safely. Another frequent problem is forcing it into an over-busy community when it would do better with more room or more deliberate tankmate choices.