Can Silver Dollar Fish Live with Koi?

A large shiny Silver Dollar breed of tropical fish

The silver dollar fish is a tropical freshwater fish from South America. The silver dollar fish resembles a dollar coin and features a tall and thin build covered in silver. Koi fish are multi-colored cold-water carp found in ponds across the world. Can silver dollar fish live with Koi?

Silver dollar fish can live with Koi fish in a tank as both species are non-territorial, friendly, and share similar water parameters and care requirements. Silver dollar fish, a tropical freshwater fish, will struggle to survive in a Koi Pond, especially during a cold winter.

When you decide to put Koi fish in a tank, you must realize that they grow quickly and will probably outgrow any tank space in a few years. Eventually, you must relocate them to a bigger tank, if possible, or to an outdoor pond. You don’t have to worry about the silver dollars, as 6 – 8 inches is their maximum size.

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Can Silver Dollar Fish Live with Koi?

Many fish owners have successfully paired silver dollar fish with Koi in a tank with no issues to speak of. Both these fish species share similar water parameter requirements and are friendly, non-territorial fish that add color and vibe to any water space.

Besides the obvious one of providing an environment that’s safe and healthy for all fish parties, what’s important is not to pair aggressive fish with placid and docile fish such as the silver dollars and Koi fish.

The passive fish may be bullied by the more aggressive fish species, especially when the bullies are as big or bigger as the mild-mannered ones. Frightened and bullied fish may struggle to come out during regular feeding times, which can lead to underweight fish and death.

Suppose you’re considering adding silver-dollar fish with Koi in a tank. In that case, you must invest in a large aquarium (250-500 gallons) for the sake of the fast-growing Koi. 

Young Koi fish can thrive and survive in a 150-gallon tank at first, but they will quickly outgrow the space; that’s why Koi fish do best in an outdoor Koi Pond with lots of water and space. 

With space requirements out of the way, let’s look at the reasons why silver dollar fish and Koi can live together by inspecting their respective care requirements:

Care RequirementsSilver Dollar FishKoi Fish
Water Temperature75°F – 82°F59°F – 77°F
Water Hardness (GH – General Hardness)4 – 15 (66 – 250 mg/liter)4 – 15 (66 – 250 mg/liter)
Level of pH6.0 – 7.56.5 – 8.5
Minimum Tank Size100 gallon (minimum of 5 silver dollars)250 – 500 gallons (young Koi
Dietary RequirementsHigh-quality flakes and pellets
Live worms
Small crustaceans
Algae wafers
Leafy greens
High-quality pellets
Live worms
Leafy greens
Average Lifespan5 – 10 years20 – 35 years
Live PlantsHornwort
Java Moss
Water Lotus
Water Lily
Water Poppy
Water Iris
Average Size4 – 6 inches20 – 24 inches (but some species of Koi can grow up to 3 feet
Regular Water ReplacementYesYes
Filtration System RequiredYesYes

When we look at the care requirements regarding water parameters of both the silver dollar and the Koi, we find that even when it’s not the same, there’s room to accommodate both in a happy and healthy environment:

Water Temperature Requirements

Silver dollars are tropical fish and enjoy warmer water in a range of 72°F – 82°F, whereas the cold-water Koi fish enjoy water temperatures ranging between 59°F – 77°F. When placing both species in a tank, ensure that your tank heater is set between 72°F – 77°F, and you should have two sets of happy fish.

Level of pH

Silver dollar fish do well in water with a pH level between 6.0 and 7.5, and Koi have no issues with a pH level in the region of 6.5 to 8.5. Keeping the pH levels at 7.0 will satisfy both fish’s needs regarding the tank water’s pH level.

If you want to learn more about pond/tank water PH levels, you can read the following blog posts here:

General Hardness of The Water

Water’s General Hardness (GH) is classified as soft or hard. General Hardness refers to the number of minerals present, typically calcium and magnesium levels. 

A GH level of 0 indicates that the water is mineral-less, which is bad for fish, whereas a GH level of more than 25 indicates water that is considered extremely hard.

Silver dollars do best in moderately soft to slightly hard water, and Koi do best in water within the slightly hard to moderately hard range.

GH (General Hardness)Value – mg/literRating
0 – 30 – 50Soft
3 – 650 – 100Moderately Soft
6 – 12100 – 200 Slightly Hard
12 – 18200 – 300Moderately Hard
18 – 25300 – 450Hard
More than 25More than 450Very Hard

Food Requirements

Regarding feeding time, it should not be difficult to feed both the silver dollar and the Koi, as their diet and food preference is very similar. 

Live Plants Requirement

Silver dollars are fish that love eating aquatic plants so much that they are called plant piranhas. Live plants in a tank stand no chance against these plant-loving critters. 

Adding hornwort and java moss is your best choice as silver dollars are not too fond of these plants, yet to put them at ease, they require lots of plant life in the tank to mimic their environment in the wild.

Koi fish kept in tanks don’t need live plants to be healthy.

In a pond setting, it’s recommended to include aquatic plants (water poppy, water lily, water lotus, and horsetail), as they provide protection from air predators and help with water filtration. These plants help to cool the water in the summertime by reflecting and absorbing the sun’s rays.

Size Compatibility

Golden and white color fish live in the black background aquarium tank with some aquatic plants.
Koi fish

It’s never a good idea to put large fish with smaller fish, as the bigger fish might see them as a morsel instead of a tank buddy. Luckily, you don’t have to worry that these two species will eat each other. 

A silver dollar can grow to 6 inches, making it quite a big aquarium fish that any Koi will struggle to eat, whether by accident or on purpose. Even when young, the Koi will not fit in the mouth of a silver dollar. Bullying between the two species won’t happen as both are hardy and tough with chilled dispositions in general.

Filtration System

Koi fish secretes a lot of fish waste, which turns into dangerous ammonia, and a good filtration system that removes waste a few times an hour is highly recommended to ensure the health of both the silver dollar and Koi.

Silver dollars are sensitive to water quality, and installing a couple of power heads will ensure the water has enough oxygen to help them thrive.

If you want to know more about what animals can live with Koi, I recently wrote a few blog posts about this subject that you can read here:

What Fish Makes the Best Tank Mates with Silver Dollar Fish?

Elegant Corydoras Cory catfish Aquarium fish fish
Cory catfish, also known as Corydoras.

Silver dollar fish are chilled, non-aggressive tank fish. As for fitting into a community made of many fish species, you’ll hardly ever see them fight with each other or cause chaos with other fish behind the rocks. They love rolling in groups and become nervous when they aren’t around other silver dollars.

Seeing that they are a wonderful addition to any fish tank, what fish will happily share a tank with silver dollar fish? Pairing them with the following bottom feeders can work beautifully:

The following cichlids will live happily with a silver dollar fish in a community aquarium:

What Fish Makes the Best Tank Mates with Koi Fish?

When looking for fish that has proven that they can co-exist with the beautiful Koi in a tank or pond, then look no further than these fish buddies:


Silver dollar fish and Koi fish can live together in harmony. The tank needs to be large, ranging from 500 – 1,000 gallons, depending on the number of each species and the size and age of the Koi. The two fish species are not aggressive by nature and will co-exist peacefully.

They will get along fine by controlling certain water parameters such as the pH level and the temperature and ensuring that a good filtration system is in place to successfully deal with the excessive waste of the Koi. With a similar taste in food, feeding time should be a breeze.

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5 Great Tank Mates for Koi Fish (Compatibility Guide 2023) | Hepper

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Guide to Koi Pond Water Hardness (Is Higher GH Better?) – Pond Informer

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