🐟 Silver Dollar (Metynnis argenteus)
A Tall, Disc-Shaped Body With a Silver Sheen and Reddish Belly • A Peaceful Herbivorous Relative of the Piranha, Growing to 20cm • Needs a Real Long-Term Tank Plan and Plant-Free Decor
 
This species grows large, reaching up to 20cm (8 inches), and we recommend a minimum aquarium size of 285L (75 gallons) for adults. Live plants will be eaten, so plan on plastic or silk alternatives from the start.
 
📋 The Silver Dollar has a tall, laterally compressed, disc-shaped body with a bright silver sheen, a slightly reddish belly, and red-tinted pectoral fins, a striking shape often compared to a coin.
It comes from South America, in shallow, heavily vegetated river margins in Guyana and across the wider Amazon basin. Every Silver Dollar we ship is feeding well.
This species shares its family with the piranha, but is a strict herbivore and genuinely peaceful, even somewhat shy and skittish at first, settling in and becoming more confident with patient, consistent care. It's a true shoaling fish, best kept in a group of 6 or more, and will eat smaller fish that fit in its mouth, so tankmate size matters. It does best in a large, dimly lit tank with open swimming space, dark substrate, and solid driftwood or rock for cover.
 
💡 Highlights
🪙 Disc-Shaped, Silver Body: A striking shape often compared to a coin
📏 Grows Large: Up to 20cm, needs a real long-term tank plan
🌿 A Strict Herbivore: Related to piranhas, but eats plants, not fish
👥 True Shoaling Fish: Best kept in groups of 6 or more
😌 Shy at First, Confident Later: Settles in well with patient, consistent care