Ternetz's Myloplus

Myloplus ternetzi is named in honour of Carl Ternetz, a prominent early collector of South American fishes, and hails from the Paraguay–Paraná basin — a drainage system that extends into subtropical latitudes. This origin means it tolerates cooler temperatures than most of its Amazonian relatives, making it an interesting option for subtropical or temperate large fish setups. It is a robustly built, deep-bodied silver pacu reaching around 35 cm.

In the aquarium Myloplus ternetzi requires a minimum of 900 litres, powerful filtration, and soft to moderately hard water. Its subtropical origin means it can be maintained at slightly cooler temperatures — down to 22°C — without stress, though warmer conditions within its range are equally acceptable. Diet is predominantly plant-based and it will consume aquatic vegetation voraciously.

This species is peaceful and companionable with other large, non-aggressive fish. It is particularly well-suited to setups housing subtropical South American species that prefer slightly cooler water. Its hardiness relative to more strictly tropical Myloplus species makes it one of the more accessible large pacu for intermediate-level large fish enthusiasts.

Water: Moderately soft, pH 6.0–7.5, 22–27°C; tolerates cooler subtropical temperatures well. Tank: 900 L minimum; robust hardscape; no live soft plants; good water circulation. Feeding: Plant-based diet; fresh vegetables, fruit, quality herbivore pellets. Breeding: No captive breeding records. Compatibility: Peaceful; excellent with subtropical SA species including temperate cichlids and tetras.