For larger aquarium owners, darting schools of silver dollar fish are a welcome sight – a fun, unique, and beautiful swirl of silvery scales flashing through. The hardy fish is great for experience or dedicated beginner aquarists alike.
Find out more of what it takes to care for these intermediate fish who love lots of room and make a beautiful, flashy display on the regular.
Quick Intro to Silver Dollar Fish
|Scientific Name:||Metynnis argenteus, Metynnis hypsauchen, Metynnis lippincottianus, Myleus rubripinnis, and Mylossoma aureum|
|Other Common Names:||N/A|
Natural Habitat, Identification, and Where to Buy
This freshwater fish is part of a huge family of fish that are called the same thing. There are many varieties with different colorings and exact detail differences. The most common fish in the aquarist hobby, however, are the Metynnis argenteus, Metynnis hypsauchen, Metynnis lippincottianus, Myleus rubripinnis, and Mylossoma aureum.
The silver dollar fish originates in the Tapajós River Basin in Brazil but is widespread throughout the shallow tributaries and rivers across South America, including around the Amazon. The fish are have flat bodies and shiny silver (where they get their name), with some species with small dots, stripes, or other markings, making the different types reasonably easy to distinguish from each other.
Silver dollar fish are part of the same family to which the piranha belongs. They’re not like their cousins, though – they’re omnivores. They’re perfect for large community tanks and are happiest in large groups – they’re schooling fish.
Silver dollars are hardy fish that live to about 10 years, making them a great fish for newbie aquarists and long-term hobbyists alike.
The fish have become popular in the fishkeeping industry, so they’re usually easy to find for a decent price at various pet stores and even online. If you’re ready to find some to care for yourself, here are some of the easiest and best places to buy them.
Most Popular Species of Silver Dollars
There are three primary silver dollar fish types that have become popular with hobbyists.
Spotted Silver Dollar Fish
As indicated by their name, the spotted silver dollar fish has a silvery body with black dots on the sides. These are found in Brazil and French Guyana. They may grow as large as 6.5 inches.
Red Hook Silver Dollar Fish
The red hook silver dollar fish has a distinct red anal fin with black trim. The coloration on this species is more obvious than many other others, so they’re easily identifiable. These whoppers can reach 22 inches in the wild, though they’ll only get to about 9 inches in an aquarium.
Tiger Silver Dollar Fish
The third popular variety is the tiger silver dollar fish. They have a clean, blue-silver body with several large, dark vertical stripes across their bodies. They’re energetic and may grow up to 6 inches in length.
Optimal Water Conditions for Silver Dollar Fish
|Water Temperature:||75 to 82 F|
|Water Flow Rate:||Moderate|
|pH:||5.0 to 7.0|
|Water Hardness:||Up to 15 dGH|
|Minimum Tank Size:||75-gallon tank|
|Optimal Tank Size:||100+ gallons|
|Optimal Tank Shape:||Standard rectangular tanks are fine|
|Recommended Filter Type:||Canister filters are best|
Because silver dollar dish are on the larger size and do best in schools, they should be housed in larger aquariums and never anything under 75 gallons. Some pieces I’ve seen discussing the topic have recommended 55 gallons as a minimum, but for optimum health and the best life possible, they really shouldn’t be in aquariums smaller than 75 gallons. Silver dollars very active fish so they need loads of room.
Silver dollars also create a lot of waste. They need to kept in a well-cared aquarium with regular cleanings but strong enough filtration as well. For this purpose, canister filters are your best bet for keeping their large tanks clean and clear. Make sure the canister filtration system is designed for a tank the size you have – anything too small won’t do it, and anything too large will potentially put out too much water flow.
Thankfully, the species is reasonably hardy, so though you do want to make sure the parameters are met, they can endure a wide range without immediately becoming ill. They do require well oxygenated water, as well, so having some air stones and power heads are recommended.
Silver dollar fish are very active and tend to be jumpers, so also make sure you’ve got a good lid on the tank.
Creating the Landscape
Well planted tanks are a silver dollar fish’s paradise. These fish naturally come from environs filled with plants – and since they’re herbivores, a planted tank not only provides them with shelter but with food. They do tend to pull up plants by their roots or eat them entirely, so be aware that any plants will become dinner time for them. With this in mind, it’s a great idea to plant prolific plants like anacharis. You may also want to include some artificial plants if you want to keep your aquarium looking lush and green.
The tank also needs plenty of open swimming area – part of why they need such a large aquarium. They should also be given dimmer lighting with plenty of shadowy spots in which they can swim and rest. And, though it seems counterintuitive, these fish aren’t really into caves. Instead, focus on giving them places where they will find deep shadows to hide in.
Physiological Considerations for Silver Dollar Fish
|Preferred Tank Region:||Middle to top|
|Scale Thickness:||Nothing of note.|
|Gill Considerations:||Standard care is all that’s needed to keep their gills healthy.|
|Swimbladder Considerations:||Nothing of note.|
|Fin Shape Considerations:||Nothing of note.|
Silver dollar fish have tall, flat bodies that area “round” in appearance, which is where they get their name from. Over the majority of their bodies, they have shiny silver scales that becomes more translucent near the fins. Their dorsal fins almost look like an equilateral triangle tilted to one side, starting at the highest point of their body and their caudal fins are forked slightly but perfectly symmetrical.
Most silver dollar fish are about 6 inches, though the larger species may get up to 9 inches in captivity or as large as 22 inches in the wild.
Silver dollar fish are wonderful for community tanks. They do best in schools and because they’re peaceful and large, they get along well with many species of peaceful fish of many sizes. They’re tough enough to handle the bigger guys and gentle enough to ignore the smaller fish species, so they’re truly a wonderful tank mate for many species.
They also tend to swim towards the top of the fish tank. Many other species prefer bottom and mid regions, so this makes them a great mix with others – still providing plenty of room for all tankmates considered.
If you’re going to keep them in a school, consider having at least 5 together.
Some of the best tank mates for these guys include:
- Blue acara
- Green severum
- Yoyo loaches
- Nerite snails
- South American cichlid species
- Bala shark
- Giant danios
- Giant gourami
- Corydora catfish
- Blackskirt Tetra
- Red tail shark
- Clown loach
- Black ghost knife
One note with cichlids. These fish may become too aggressive during spawning time to house with silver dollars. Be sure to isolate them in breeding tanks for this reason to keep your silver dollars healthy and stress free.
Gender, Breeding, and Reproductive Considerations
If you decide you’d like to breed your own silver dollar fish at home, thankfully, you’re in luck. These fish are relatively easy to spawn in captivity.
To get started, you’ll need a mated pair. Most folks find the best success with keeping their fish in groups and raising them together from juveniles. The fish reach maturity around 1 year of age. They’ll typically be about 4 inches long at this point.
Males have longer anal fins that have a red tinge towards the front. During courting, they will also develop two large black spots behind the base of their pectoral fins.
When you discover your mated pair, separate them from the rest of the school into a breeding tank. The breeding tank should be shallow and at least 40 gallons in size. The water should be between 79 and 82 degrees Fahrenheit, with a pH of 6.0 to 7.0 and a hardness between 4 and 8 dGH.
Add java moss and other floating plants to the tank.
When you have them in the new tank, condition them to spawn by doing a few things.
- First, feed them high quantities of plants and vegetables.
- Pay attention to their coloring. When the male’s coloring darkens, especially around the caudal, anal, and dorsal fins, he’s ready to spawn.
- Use a sponge filter to provide them with a gentle water flow.
- Now, dim the lights and wait. You’ll notice the male start to chase the female around the tank.
When the female is ready to spawn, she will lay up to 2000 eggs near the floating plants. The eggs will be transparent and slightly yellow in coloring. They will sink to the bottom of the tank. The male will then fertilize the eggs.
At this point, the parents should be removed from the breeding tank and returned to the main tank. This will protect the fry as they hatch. The parents don’t generally eat them, but they’ll need plenty of space to develop.
The eggs will hatch about 3 days after they’re lain. The fry will swim freely within about 6 to 9 days.
To feed the fry, use infursoria types foods, small plankton, brine shrimp nauplii, and veggie flake food.
Silver dollar fish should be fed 2 to 3 times a day. They’re highly energetic and active, so they burn through their meals quickly. Of course, they will eat any live plants you’ve got, so they’ll not constantly be ravenous.
They love vegetable flakes made from spirulina and algae wafers. They also thrive on your garden offerings: lettuce, watercress, cooked romaine and spinach, peas, squash, carrots, chickweed, cucumber, spring greens, boiled potatoes, and fruit. Be sure to remove any uneaten foods to prevent them from rotting and causing health issues for your silver dollars and their tanks mates.
Though these fish are herbivores, they may occasionally enjoy some meaty treats like bloodworms and glass worms or brine shrimp. Toss in some seaweed and they’re in heaven.
The best foods for them include:
- Veggie flakes
- Cooked romaine
- Cooked spinach
- Boiled potatoes
- Algae wafers
- Spring green
|Best Sustenance Food Type:||Veggie-based flakes, spirulina, seaweed flakes, and fresh veggies (plus those live plants)|
|Additional Food For Optimal Health:||The occasional meaty treat like bloodworms, glass worms, or brine shrimp|
|Special Foods and Considerations for Best Color and Growth:||A balanced diet of veggies flakes, fresh and cooked vegetables, and the occasional meat-based protein treat|
|When and How Often to Feed Fish Based on Life Cycle:||They should be fed 2 to 3 times per day – according to the best schedule for you.|
Common Diseases and How to Avoid and Treat Them
Silver Dollars have a reputation for being a hardy fish. However, they are just as susceptible as any fish when it comes to problems with their water. Aquariums are a closed system so the tank naturally starts to build up toxic substances like phosphorous, nitrate, and decomposing matter.
To prevent your fish from becoming sick due to toxins in the water between 25-50% of the tank in the water must be replaced at a minimum of every two weeks.
Another potential source of illness and infection for your Silver Dollar is when you introduce something new to the tank. Make sure that any decorations or rocks you had to the tank have been completely cleaned. Any new fish need to be observed to make sure they are okay.
Many diseases can be prevented by making sure you have a clean tank and high water quality.
A very common disease that occurs in ornamental fish is an ectoparasite called Ich or white spot disease. This is noticeable because your fish begin to develop white spots on fins, scales, and gills. This ectoparasite depends on water temperatures stay cool so if your water gets above 77F it won’t be able to live, and the high temperature can even help prevent an outbreak.
There is no species-specific disease that afflicts Silver Dollar fish.
|Best Antibiotics:||Store-bought antibiotics will work fine.|
|Treatments to Avoid:||There are no treatments to avoid.|
|Food Recommendations When Sick:||A hearty diet with fresh food is best.|
|Hospital Tank or Isolation Withing the Community Tank:||Hospital tank is the best choice for sick fish.|
4 Facts About Silver Dollar Fish
- The silver dollar fish is a close relative of the piranha and pacu fish. Thankfully, they don’t have those nasty razor-sharp teeth like their cousins!
- The silver dollar fish is known as such because of its extremely flat appearance, somewhat resembling that of a silver dollar coin.
- Silver dollar fish are omnivores but they primarily feed on plant matter. Your aquarium plants are their favorite food!
- There are 16 species of silver dollar fish across two genera.