Silver dollar care
Metynnis argenteus · Tapajós River basin, Brazil
Silver dollars are round, plate-shaped relatives of the piranhas that eat plants, not fish.
- Tank size
- 75 US gal or larger
- Temperature
- 75 to 82 °F (24 to 28 °C)
- Group size
- 5 or more
- Temperament
- Peaceful
- Adult size
- 6 in
- pH
- 5.5 to 7.5
- Hardness (GH)
- 4 to 15 dGH
- Lifespan
- 8 to 10 years
- Diet
- Herbivore
- Care level
- Easy
In a 75 gallon
48½ × 18½ × 21⅛ in outsideHow to keep silver dollars
Silver dollars are round, plate-shaped relatives of the piranhas that eat plants, not fish. Keep five or more in a 75 gallon or larger tank at 75 to 82 °F with plenty of swimming room; they are gentle with small fish and sturdy enough for big ones.
Diet: Herbivore: vegetable flakes and pellets, blanched greens, some frozen foods. Fish food types compared · how often to feed.
Where they swim: Middle of the tank.
Silver dollar tank mates
Share the temperature and water, and neither side eats, nips or bullies the other. Check the full group in the stocking checker.
Bristlenose pleco
6 in · 29+ gal · 73–81 °F
Siamese algae eater
6 in · 29+ gal · 72–80 °F
Giant danio
6 in · 55+ gal · 72–79 °F
Three-spot (blue) gourami
6 in · 29+ gal · 72–82 °F
Firemouth cichlid
6 in · 40+ gal · 75–84 °F
Yoyo loach
6 in · 40+ gal · 75–82 °F
Rainbow shark
6 in · 55+ gal · 72–80 °F
Red-tail shark
6 in · 55+ gal · 72–79 °F
Keep apart
White cloud mountain minnow: No shared temperature: silver dollars need 75 to 82 °F, white cloud mountain minnows 64 to 72 °F.
Oscar: Oscars are aggressive towards peaceful fish such as silver dollars.
Pea puffer: Pea puffers belong in a tank of their own.
Fancy goldfish: No shared temperature: silver dollars need 75 to 82 °F, fancy goldfish 64 to 74 °F.
Convict cichlid: Convict cichlids are aggressive towards peaceful fish such as silver dollars.
Jack Dempsey: Jack Dempseys are aggressive towards peaceful fish such as silver dollars.
What a silver dollar tank needs
A tank of 75 US gallons or more (such as the 75 gallon) with a tight lid (they jump), and the equipment below.
As an Amazon Associate I earn from qualifying purchases.
Aqueon QuietFlow Canister Filter 300
Rated by the maker for 55–75 US gal, which covers a 75 gallon silver dollar tank without being built for a far bigger one.
Marineland Penguin PRO 375
Rated by the maker for up to 75 US gal, which covers a 75 gallon silver dollar tank without being built for a far bigger one.
Aqueon Pro 200
Silver dollars need 75 to 82 °F; most homes run cooler, so a heater holds the temperature.
API Freshwater Master Test Kit
Tests ammonia, nitrite, nitrate and pH, the readings that matter most before and after adding silver dollars.
Seachem Prime 100 mL
Removes chlorine and chloramine from tap water at every water change.
Fluval Edge Thermometer
Shows the water temperature at a glance, so you know it stays within 75 to 82 °F.
More choices, each with the reason it is in or out: Filters for a 75 gallon tank · Heaters for a 75 gallon tank. We don’t list fish food: any good brand of the foods under Diet will do. Plan the whole tank's equipment →
Common silver dollar problems
- They eat almost every live plant; use java fern, anubias or silk plants.
- A lone silver dollar is skittish and dashes into the glass; keep a group with cover behind it.
Test the water first whenever fish look unwell: see what your readings mean, then match the symptom. For disease, a vet who treats fish can diagnose it and advise treatment.
More to compare
Sources
Name, origin and adult size checked against Wikipedia: Metynnis argenteus. Temperature, pH, hardness, group size, lifespan and minimum tank size are common hobby guidance, not figures from that article. Ranges are the range the species tolerates; aim for the middle. Minimum tank sizes are for an adult group. Drawings are our own; photo credits follow.
Photo credits
Real photographs from Wikimedia Commons, resized and cropped to fit; each is used under the license named.
- Silver dollar Greg Hume, CC BY-SA 4.0, via Wikimedia Commons
- Bristlenose pleco André Karwath aka Aka, CC BY-SA 2.5, via Wikimedia Commons
- Siamese algae eater aleander2137, CC BY-SA 4.0, via Wikimedia Commons
- Giant danio Faucon, CC BY-SA 2.5, via Wikimedia Commons
- Three-spot (blue) gourami Peter Jung, CC BY-SA 3.0, via Wikimedia Commons
- Firemouth cichlid H. Zell, CC BY-SA 3.0, via Wikimedia Commons
- Yoyo loach Orishas92, Public domain, via Wikimedia Commons
- Rainbow shark MerlinSenger, CC BY-SA 3.0, via Wikimedia Commons
- Red-tail shark Astellar87, CC BY-SA 4.0, via Wikimedia Commons
- White cloud mountain minnow Petrtyl, CC BY 4.0, via Wikimedia Commons
- Oscar H. Zell, CC BY-SA 3.0, via Wikimedia Commons
- Pea puffer Beta Mahatvaraj, CC BY-SA 4.0, via Wikimedia Commons
- Fancy goldfish Benson Kua, CC BY-SA 2.0, via Wikimedia Commons
- Convict cichlid S. Olkowicz, CC BY 2.5, via Wikimedia Commons
- Jack Dempsey Sviemeister (English Wikipedia), CC BY 2.5, via Wikimedia Commons
- Neon tetra Holger Krisp, CC BY 3.0, via Wikimedia Commons
- Cardinal tetra CHUCAO, CC BY-SA 3.0, via Wikimedia Commons
- Black neon tetra Debivort, CC BY-SA 3.0, via Wikimedia Commons
- Green neon tetra Sascha Biedermann, CC BY-SA 2.5, via Wikimedia Commons
.jpg){kind=link}
.jpg){kind=link}
.jpg){kind=link}
.jpg){kind=link}
