Sauron silver dollar

Myloplus sauron

Also known as Black bar silver dollar, Eye of Sauron dollar

FreshwaterFish

Sauron silver dollar (Myloplus sauron) — The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature: 79–86°F (26–30°C)
pH: 5.5–7.0
Adult size: 11.8 in (30 cm)
Minimum tank: 159 gal (600 L)
Temperament: Mostly peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: No record
Rarity: Rare
Origin: Rio Xingu basin, Brazil
Family: Serrasalmidae

Overview

The Sauron silver dollar is a round, silver schooling fish that needs company, so keep at least five together to keep them settled and confident. They swim in the middle levels and are peaceful with other fish, but they reach a good size and graze plants, so house them with calm, similarly sized tankmates in a large tank of around 600 liters or more. Expect soft plants to be eaten, and stick to hardy species or decor instead. Their diet is mostly vegetable, so offer blanched vegetables, spirulina, and pellets, rounded out with occasional frozen foods. They like warm, fast, well-oxygenated water and plenty of room to move as a group.

In the wild

This species lives only in the Rio Xingu basin of Brazil, a warm, clear-water river known for fast, oxygen-rich current running over rock and sand. To suit it, keep the water hot, from about 26 to 30 C, at a soft, slightly acidic to neutral pH between roughly 5.5 and 7.0, and drive good flow through the tank. A Xingu-style layout of smooth rounded stones, sand, and open channels of moving water fits it, with bright but not harsh light. As with other silver dollars, delicate plants will not last, so lean on hardscape.

Good to know

Myloplus sauron is a plant-eating pacu in the family Serrasalmidae, described in 2024 from populations once folded into Myloplus schomburgkii. It grows to around 30 centimeters, with a tall, coin-shaped body crossed by a single vertical black bar that tapers at both ends. Like its relatives it has flat, almost human-looking teeth suited to chewing vegetation rather than the shearing teeth of a piranha. It has not been bred in the aquarium, so stock comes from the wild.

Did you know

Scientists named this fish sauron in 2024 because the black bar and pale body on its round flank reminded them of the fiery, slit-pupiled Eye of Sauron from The Lord of the Rings.

Tank mates

Sauron silver dollar is a mostly peaceful, schooling species that keeps to the middle. These picks match on water type, temperature, pH, size and temperament.