Diamond Myleus

Myleus rhomboidalis takes its species name from its distinctly diamond-shaped, rhomboidal body outline, which gives it a particularly elegant profile among pacu species. Native to the Amazon basin, it inhabits slow-moving and flooded forest environments where it browses on aquatic plants and fallen fruits. Its large, highly iridescent scales catch and reflect light spectacularly, making it a visually outstanding display fish.

This species requires a minimum 800-litre aquarium, clean and warm water, powerful filtration, and a mostly open layout. Like all Myleus, it will consume soft-leaved aquatic plants and should only be housed with artificial vegetation or extremely robust species like Bolbitis or sturdy Anubias secured to rock. Sandy or fine-gravel substrate is preferred, and strong lighting helps showcase its iridescent scales.

Myleus rhomboidalis is peaceful and tolerant of other large, non-aggressive species. It does particularly well in groups of three or more of its own kind. A plant-rich diet supplemented with spirulina-based pellets and fresh vegetables will maintain health, growth rate, and the metallic body sheen that makes this species so attractive to collectors.

Water: Soft to moderately hard, pH 5.5–7.5, 24–28°C; pristine conditions with regular large water changes. Tank: 800 L minimum; sandy substrate and open swimming space; robust hardscape only. Feeding: Vegetable-based — cucumber, rocket, spinach, fruit, spirulina pellets, and algae wafers. Breeding: No documented captive breeding; seasonal cues in origin habitat suggest complex requirements. Compatibility: Peaceful with large non-aggressive SA species; ideal companion for other Myleus.