Silver Dollar Fish Overview, Care & Breeding Guide

The silver dollar fish is hardy, so it rarely falls sick. This makes it perfect for any beginner aquarist. With good water conditions and other basic care, you won’t have to worry about the fish falling sick!

What is Silver Dollar Fish?

Silver dollar fish is a unique fish for your freshwater community tank due to its rhombic body and silver color that make it stand out and easy to identify.

OriginRio Tapajos drainage area in Brazil
Scientific NameMetynnis argenteus
Common NamesSilver dollar fish, silver dollar, plant piranha
IUCN Red List StatusLeast Concern
AppearanceRhombus-shaped, silver-colored fish, with transparent fins
SizeFemales: 12-15 cm (5-6 in), males slightly smaller
Lifespan5-10 years, max: 12 years
TemperamentUsually peaceful, males show aggression during mating season
Tank LevelTop to middle-dwellers
Water Temperature75-82 °F (24-28 °C)
pH Level5-7
Water Hardness4-15 dGH
Care LevelEasy
Minimum Tank Size75 gallon for 5
Tank EnvironmentSpacious, dimly lit, with hiding spaces
DietPrimarily herbivorous, but accepts omnivorous diet
Tank MatesOwn group, similar sized and slightly larger peaceful species

What is the Natural Habitat for Silver Dollar Fish?

The silver dollar fish is naturally from the Rio Tapajos drainage area in Brazil. It is also found in the shallow tributaries of most rivers across the northern side of South America.

The slow-moving rivers and streams and the still water bodies, like lakes and swamps, of Guyana and the Amazon River basin are its home.

According to The IUCN Red List of Threatened Species assessment of 2020, the silver dollar fish is listed as Least Concern.

Which family does Silver Dollar Fish belong?

The fish belongs to the Characidae family under the Characiformes order and is scientifically known as Metynnis argenteus.

However, the fish is popular worldwide by a variety of names, like silver dollar fish and silver dollar.

It is native to the same waters as the piranha. So, it has an interesting nickname too, the ‘plant piranha.‘ because it chows down on plants quite happily!

There are about 14 different species under the Metynnis and Myloplus genera.

Out of them all, Metynnis argenteus is considered the primary silver dollar in the aquarium trade. In the entire article, we will refer to M. argenteus while referring to the silver dollar fish.

Fun Fact: The silver dollar fish got its name because the juveniles resemble the 19th-century $1 coin.

How does Silver Dollar Fish look?

2 silver dollar fish

What is the Size of Silver Dollar Fish?

The adult female silver dollar fish is known to grow up to 12-15 cm (5-6 in), and the adult male fish is known to be a little smaller. Some specimens may grow up to 20 cm (8 in).

The maximum reported weight of the fish is 153 g.

What is the Color of Silver Dollar Fish?

The silver dollar fish, as suggested by its name, primarily has a silvery body. But it’s not uniformly silver and sparkles with different colors depending on the light source and the angle of lighting.

Sometimes, it shows a bluish or greenish tint with reddish hints. It might have small colored dots on its sides and some reddish tinges on the anal fin.

What are the Features of Silver Dollar Fish?

The silver dollar sports an interesting rhombus-shaped lumpy body that is tall and flat. The downward slant begins where the dorsal fin starts. The bottom half of the body is flat until the sharp turn at the tail fin.

It has transparent dorsal and anal fins. The dorsal fins have a triangular shape and are placed on the highest point of the body. The caudal fin is slightly forked and very symmetrical.

The fish has often been confused with its close relative Metynnis hypsauchen – both look similar and have similar care instructions. However, you can tell them apart by the black blotch above and beyond the eyes of M. hypsauchen.

How is a male and female Silver Dollar Fish different?

Usually, the adult female silver dollar fish is larger than the male. The female has transparent tail fins and is mostly silver in color.

The male fish develops a red tinge on its gills and mouth during the breeding season. It has a red-edged tail and you will also notice some intense red-orange color throughout its body. It also shows two large dark spots at the pectoral fin base.

Further, the male has a slightly longer anal fin than the female, which is also tinted with red in the front.

Some male specimens also sport a yellowish-to-white “egg spot” on their anal fin to attract females, while the others also flaunt a black marbling pattern on their bodies.

What is the behavior of Silver Dollar Fish in the tank?

The silver dollar fish is a peaceful and friendly species and must be kept in a school of at least 5. Otherwise, the species can get nervous and shy and also be isolated and stay hidden out of fear.

It becomes active in a group of its own and can cope well with bigger, peaceful species as well when kept in a school. It is pretty hardy and won’t easily get bullied by bigger fish.

However, during the breeding season, the male fish becomes territorial and aggressive.

What is the Lifespan of Silver Dollar Fish?

The silver dollar fish usually lives for up to 5-10 years. But in my experience, with the best care in captivity, it can live up to 12 years.

Author’s Note: This fish has been known to jump out of the aquarium, so secure a tight lid on your tank!

How to take care of Silver Dollar Fish?

Yellow cichlid surrounded by 3 metynnis argenteus fish

If you want this fish as your pet, you need to provide it with the best care. So, follow the below instructions here.

What is the Tank Size of Silver Dollar Fish?

As this is quite a large fish, you will need a big tank to accommodate it. It likes to be housed in shoals of 5-6 members, for which a tank of 75 gallons or more is required.

If you add more silver dollar fish to the tank, increase the capacity by 10-15 gallons per fish.

What is the Water Chemistry for Silver Dollar Fish?

When it comes to water parameters, the fish is extremely demanding. So, to keep it happy, follow this information very closely.

  • pH Levels: 5-7
  • Water Temperature: 75-82 °F (24-28 °C)
  • Water Hardness: 4-15 dGH
  • Ammonia: 0 ppm
  • Nitrite: 0 ppm
  • Nitrate: Below 20 ppm

What is the Tank Environment for Silver Dollar Fish?

To make your silver dollar feel at home and thrive, make sure you arrange your tank as we have suggested below.

Which Substrate is best for Silver Dollar Fish?

A dark fine-grain gravel substrate is ideal for this fish as it will mimic its natural home and encourage it to forage properly.

But being a top and middle-level dweller, the fish doesn’t stay on the bottom for too long. So, you can also go for a dark sand substrate if other bottom-dwelling species need sand.

Which Plants are to be kept in Silver Dollar Fish tank?

The natural environment of silver dollar fish is highly vegetated.

It is known to eat plants, so do not keep live plants in your tank. Instead, use plastic plants for decoration.

If you wish to choose a live plant for this tank, pick one with tough leaves, like Anubias, hornwort, or java fern.

Which Lighting should a Silver Dollar Fish tank have?

The fish prefers dim lights, so use a low-powered light for this tank. Soft, subdued lighting makes your tank environment identical to that of the lakes it inhabits. This encourages the fish to come out of hiding and swim around.

What is the suitable Décor for Silver Dollar Fish?

Before you add any sort of decor, plan well so you keep a lot of free-swimming space in the tank. Then, you can add some rocks, caves, driftwood, and likewise to offer some hiding spots for the fish.

What type of filter is needed for Silver Dollar Fish tank?

A small oxygenating filter should be added to this tank to maintain a well-filtered and aerated water quality. You can use an air-powered sponge filter for this.

What is the Water Flow Rate for Silver Dollar Fish tank?

As the silver dollar fish lives in slow-flowing or still water, try to mimic that condition and provide gentle flowing water in the tank.

Fish Care Tip: Never exceed 88 °F (31 °C) in the silver dollar fish tank for long periods.

What is the food and diet of Silver Dollar Fish?

The silver dollar fish is omnivorous but prefers plant-based feeds and likes only a few meaty treats from time to time.

So, choose the plant-based foods from this list for its diet and offer a little meat intermittently:

  • Vegetable flakes
  • Spirulina
  • Lettuce
  • Watercress
  • Cooked romaine
  • Spinach
  • Cooked peas
  • Cooked squash
  • Cucumber
  • Chickweed
  • Cooked carrot
  • Courgette
  • Spring greens
  • Fruits
  • Boiled potatoes
  • Algae wafers


  • Bloodworm
  • Mosquito larvae
  • Glassworms
  • Brine shrimp

Feed it with little portions eaten within 3 minutes several times a day but be careful not to overfeed the fish.

Use feeding rings to ensure that the most active fish does not steal all the food from the slow ones.

Which Tank Mates should Silver Dollar Fish have?

Species that occupy the bottom of the tank are a good choice for silver dollar tank mates. You can add large, peaceful fishes to this community tank. A few tank mates might be, namely:

Which Tank Mates to Avoid with Silver Dollar Fish?

Avoid the following types of tank mates for a tank of silver dollar fish:

  • Small fish: Your silver dollar might eat these fish, mistaking them as a snack.
  • Fin nippers: They might attack the fins of your silver dollar fish.
  • Aggressive fish: They may stress your pet fish.

Some of such fishes are namely:

  • Betta fish
  • Neon tetra
  • Small gourami
  • Chili rasbora
  • Endler’s guppy
  • Nano fish
  • Freshwater angelfish

What are the Common Diseases in Silver Dollar Fish?

This fish is extremely resistant to diseases and will rarely get sick. However, you must still know the common freshwater fish diseases to ensure quick identification and treatment.

Disease NameCausesSymptomsTreatment
IchProtozoan Parasitic InfectionFlashing, white spots, inactivity, appetite lossRaise water temperature, add aquarium salts or ich medication
Fin rotBacterial InfectionFin discoloration or redness, inactivity, appetite loss, fin disintegration, fin frayingImprove water quality, remove any object that may hurt the fish, and add antibiotics
ColumnarisBacterial InfectionInactivity, appetite loss, fin fraying, white patchesReduce stress, add antibiotics, and enhance water quality
Skin flukesParasitic InfectionRed spots, breathing difficulties, tiredness, excess mucus, flashing, missing scales, hazy skin, appetite lossImprove water quality, give nutritious diet, oral medications, medicated baths, or injections

Quick Tip: Change 20-30 % of the water each month to maintain cleanliness.

How to Breed a Silver Dollar Fish?

Breeding this fish is easy in a home aquarium. In fact, it spontaneously spawns when the aquarium conditions are comfortable. Here’s a quick guide to help you do that.

1. Specimen Obtaining & Conditioning

The fish is a group spawner by nature, but it can also be mated in pairs. To find a good pair, look for fish that have been raised together in a shoal since they were juveniles.

You can also raise 6 juveniles together and wait until they sexually mature, i.e., when they’re one year old and 4 inches long.

Once you get a mated pair, isolate them from the rest. Condition them by feeding high-quality plants and vegetables for 7-10 days. Feed them meat from time to time.

Some say that you can get better results if the male and female are isolated during the conditioning.

2. Tank Preparation

Invest in a spawning tank of about 40-gallon capacity if you’ll breed only one pair. But if you’ll mate them in a group, a large tank of 150 gallons is necessary.

Fill it with freshwater with the following water chemistry:

  • Water Temperature: 79-82 °F (26-28 °C)
  • pH Levels: 6-7
  • Water Hardness: 4-8 dGH

Add some plants like java moss and spawning mops to catch the eggs. Keep floating plants in the breeding tank to make the fish think they are in a suitable place to spawn.

Install a small air-powered sponge filter to maintain pristine water conditions and suitable gentle water flow. Use subdued lighting to make the fish feel confident to approach each other. Perform water changes with warmer water to trigger spawning.

3. Mating Process

The male fish’s anal, caudal, and dorsal fins darken, and the redness around the chest brightens when it is ready to spawn. It chases the female and rubs its bodies together.

When ready, the egg scatterer female fish lays about 300-2000 transparent to slightly yellow non-adhesive eggs that fall to the tank bottom and leaves of plants.

The male then externally fertilizes the eggs.

4. Parent-Fry Separation

This fish does not harm its eggs, but the adults should be separated from the incubating eggs to ensure optimal fry development.

5. Incubation & Fry Development

The egg incubation will take about 3 days, after which these will hatch. For about 6-9 more days, the fry will be free swimming. Until then, they consume the nutrients from their egg sacs.

When they swim freely, feed the fry:

  • Commercially prepared fry food
  • Finely crushed spirulina
  • Freshly hatched artemia nauplii
  • Milled salad leaves
  • Small planktons

The juveniles will become adults after 6-8 months.

Breeding Tip: To ensure you only have healthy specimens, cull the fry that look deformed or are too small compared to the remaining batch of juvenile fish.

How to Buy Silver Dollar Fish?

Make sure there are no white spots on the fish you are buying as this is a sign of a fish suffering from ich disease.

A healthy fish will be alert, have firm fins, and wiggle its butt while moving.

A word from FishInAquarium

The silver dollar fish is quite an active and playful species when kept in groups. A bunch of this curious fish in your tank is bound to create an entertaining view. It’s also not too expensive, so you can easily bring a small group home!

So, if this article convinced you to give this species a chance, share this with other fish enthusiasts. Let your friends know more about this amazing fish.

However, if you have any questions or concerns, drop us an email, and we will get things sorted in no time!

Minnie B Miller - Professional aquarist and owner of FishInAquarium

About Minnie B Miller

Minnie B. Miller, a professional aquarist and owner of FishInAquarium, has over 8 years of expertise in fish breeding and care, gained through her roles at AquaticTX and Sea Lion Landing. Having honed her skills with various aquatic species, she is dedicated to empowering fellow enthusiasts by sharing her knowledge and experience.