Goldfish are one of the most popular aquarium fish in the world. Their friendly personality, beautiful colors and active nature make goldfish a favorite with both new and seasoned aquarists. But how many people have ever asked how to set up a goldfish aquarium? I know I didn't when I got my first goldfish!
Most people put very little thought or effort into setting up their goldfish tank. That probably has to do with the fact that people have seen “Goldfish bowls” for decades. You see goldfish bowls in movies and on television. But perhaps the most people think of the goldfish toss at fairs and carnivals. If you tossed a coin or ping pong ball into the bowl, you won a goldfish. At least that's how I got my first goldfish!
Unfortunately, this has led people (including me) to assume goldfish are a “bulletproof” toy fish that can survive in even the worst conditions. However, the truth is, goldfish have specific care requirements needed for a healthy life. But if you provide these needs and treat them well, goldfish can live for 10 years or longer.
This article will cover everything you need to know about properly setting up your very own goldfish aquarium. But first, let’s explore how fancy goldfish came to be the world’s favorite pet fish.
The Origins of the Goldfish
Today there are hundreds of varieties of exotic goldfish. But today’s goldfish look nothing like their Chinese ancestors – the common carp.
Goldfish originated from fish we know as the common carp. These carp generally have a drab olive color with ordinary fins. Carp were raised for food, not pets.
However, occasionally a baby carp would grow and develop a tinge of yellow, red or orange coloration (see the image below). These curiosities were placed in a separate pond instead of being eaten. Over the years theses “unusual” fish bred and eventually developed brighter colors that were “locked” into their genetic code.
Chinese fish enthusiasts began selectively breeding these fish before 1000 AD. After hundreds of years of careful crossbreeding eventually the “goldfish” was created. Once goldfish were introduced to Japan, breeders developed fish with fancy tails and specific color patterns.
All the magnificent forms, shapes and colors we know today began as the humble carp. While carp are quite hardy and are considered an invasive species, fancy goldfish are much more delicate.
If you want your goldfish to look their best and to provide years of companionship and entertainment, forget the bowl and go with an aquarium. An aquarium is the best way to care for, and display, your prized fish.
Here’s how to set up a goldfish tank.
Choosing A Goldfish Aquarium
Fish shops usually stock small, immature goldfish. Even the more exotic Ryukins and Orandas are often sold as tiny 3-inch (8 cm) fish. They’re cute and, to the novice, look like they could live in a bowl or tiny aquarium. But goldfish grow fast. Fancy goldfish can grow to the size of a grapefruit! A Sarasa Comet will grow over 12-inches (30-cm) long.
As a result, goldfish need lots of room to swim and explore. Crowded fish are unhappy fish and the stress from overcrowding can suppresses their immune system, leading to health issues like bacterial and fungal disease problems.
That’s one of the reasons why a larger aquarium is best for keeping goldfish. You can keep one or two small goldfish in a 10-gallon aquarium but be prepared to clean the tank more often and move them to a larger tank as they mature. A 30 to 55-gallon aquarium has proven to be the ideal tank size. We've included links to the best 10, 20, and 55 gallon goldfish aquarium kits on Amazon below. We think the 55-gallon aquarium from Tetra would be the best goldfish aquarium setup.
Last update on 2023-03-20 / Affiliate links / Images from Amazon Product Advertising API
Remember, smaller tanks are not necessarily better or easier for beginners! Here’s why a larger tank is better for goldfish.
Goldfish love to swim and explore their surroundings. Some varieties really enjoy foraging through the gravel.
When goldfish are packed too tightly in an aquarium, they can bump into each other or even get a little aggressive. Even the tiniest fin tear or lost scale can be an opportunity for an infection.
The fancy goldfish with long, delicate fins, bubble eyes and lionhead features are much more delicate. They need room to move around without rubbing on ornaments or bumping into another fish.
Another thing to remember is that Goldfish are omnivores. They eat plant and animal food sources like bits of algae, worms, tiny crustaceans and even fish eggs if they can find them.
Unlike other fish, goldfish don’t have a traditional stomach. They quickly process their food and send the solid waste into the aquarium. As a result, larger goldfish can create a lot of fish poop!
As you can imagine, stuffing a goldfish into a tiny tank is like living in a cramped toilet. Larger aquariums provide a “dilution factor” that reduces the chances of waste products building up to harmful levels. The greater ratio of gallons per fish provides a safety factor, allowing nature to detoxify ammonia, nitrite and solid fish waste.
Larger goldfish aquariums also provide room for the fish to swim and display their beautiful fins and coloration.
Choosing a Filter for a Goldfish Aquarium
While carp thrive in murky low-oxygen ponds, goldfish require clean well-oxygenated aquarium water.
An external hang on the back (HOB) (our top pick on Amazon) power filter is the best option for most goldfish tanks. The cartridges capture floating debris and Activated carbon inside the cartridges removes natural organics that build up in the water. Many of these organics will discolor the aquarium water, giving it a tea-like tint, detracting from the tank’s beauty. HOB filters also distribute the water flow evenly through the tank, which is perfect for goldfish.
Power filters also have the advantage of providing a high flow rate without causing strong currents in the aquarium. Fancy goldfish are not strong swimmers. If the water flow is too aggressive, they’ll struggle to swim, constantly battling the currents.
For larger goldfish aquariums, a canister filter is probably the way to go. You’ll be keeping more fish (or larger fish) in a big aquarium. This means more fish waste and bits of debris will be formed in the tank. Canister filters contain more filtration media and use higher flow rate water pumps to get the job done.
Many canister filters come with return flow accessories like spray bars and nozzles. This makes it easy to direct water flow throughout the tank without blasting the goldfish. The idea is to have all the water in the tank gently swirling around. This stirs up debris, so it can be removed by the filter. Surface agitation also drives oxygen into the water and carbon dioxide out.
Choosing Lighting for a Goldfish Aquarium
A LED aquarium light fixture is ideal for a goldfish tank. LED lights run cooler than fluorescent lights, which helps keep the water cool. A daylight-style LED fixture will bring out the goldfish’s natural colors. White and red colors will “pop” without looking artificial.
Many LED aquarium lights come with digital timers that turn the light on and off automatically. Some models even have a remote control for dimming the lights or changing the color inside the aquarium. Check out our guide for choosing LED lighting here.
The LED light below comes in a variety of sizes that can fit tanks both large and small; has both blue and white lighting for day and night; is powerful enough for planted tanks; is compatible with their automatic timer that simulates sunrise and sunset; and is one of the best values on Amazon in our opinion (and many other reviewers).
|NICREW ClassicLED Aquarium Light, Fish Tank Light with Extendable Brackets, White and Blue LEDs,...||$43.49||Buy now on Amazon|
Last update on 2023-03-20 / Affiliate links / Images from Amazon Product Advertising API
Ideal Water Conditions for a Goldfish Aquarium
While goldfish require proper care just like any other aquarium fish, they’re don’t require special water conditions. They thrive in a wide variety of pH ranges. Just be sure the pH does not fall into the acidic range, below 6.8. As with all aquarium fish, ammonia and nitrite should always be zero. Use a test kit to monitor these water quality parameters.
Goldfish are particularly sensitive to chronic exposure to nitrite. They respond to nitrite by developing dark red blotches on their body. It has been described as bruise-like patches. Nitrite prevents the blood from carrying oxygen to the brain and other vital organs. This is an emergency situation that should be treated immediately until the nitrite level is brought under control.
Water hardness is not critical. Goldfish thrive even in very hard water. However, KH (alkalinity) is important to monitor. KH is the level of bicarbonate and carbonate in the water. KH is responsible for neutralizing acids and keeping the pH stable. Water changes usually replenish KH and keep the pH in the correct range.
Below is a list of water parameters suitable for keeping a goldfish aquarium. pH - 6.8-8.2
• Ammonia- 0.0
• Nitrite – 0.0
• GH/KH – 6-10 degrees
• Water temperature – 65-75°F
Ideal Water Temperature for a Goldfish Aquarium
Unlike tropical fish, goldfish prefer cooler water with 65-75°F being ideal. Avoid setting up the aquarium where it will be exposed to a close heat source like a fireplace or direct sunlight for more than a few hours per day.
Experienced goldfish keepers use an aquarium heater to prevent temperature fluctuations, specifically a rapid drop in temperature. A good practice is to set your aquarium’s heater to 70°F as a safety measure, especially if you keep your home at a cool temperature.
Aquascaping a Goldfish Aquarium
Goldfish like to sift through the substrate. They’ll peck at the gravel looking for bits of food. It’s their nature. But don’t allow food to settle into the gravel bed. It will just decay and cause water quality problems like cloudy water, algae growth and nitrite spikes. Any aquarium-safe gravel will work with goldfish.
If you’re decorating the tank with plastic, silk or even cool-water live plants, goldfish may try to dig them out. Placing a few smooth larger pebbles or rocks around the base of your plants will discourage digging.
Don’t use ornaments with sharp, rough or pointy edges. Telescope and bubble-eye goldfish can’t see as well as other goldfish fish. They can accidentally scratch themselves on sharp objects. Keep this in mind when decorating the goldfish aquarium, especially when keeping fancies.
Goldfish Aquarium Maintenance
Goldfish create a lot of solid waste. A good aquarium filter will capture some the solids in the filter media. It’s important to change filter cartridges every 30 days to keep the filter working efficiently. Even large canister filters need monthly servicing.
Remember, organic matter like fish waste and uneaten food will decay inside the filter if not removed every few weeks. Decomposing organics send algae-promoting nutrients, like phosphate, into the water. Organics also create conditions favorable to disease-causing organisms. But changing the filter media is not enough.
As waste collects in the gravel bed, it forms a dark sludge layer. Pathogenic bacteria and parasitic worms are known to thrive in dirty, organic-rich gravel. Use a gravel siphon to keep the gravel clean. Once a month lightly vacuum the gravel to remove debris.
Gravel cleaning is a great way to make a partial water change too. You’ll want to remove about 20% of the water every month. Water changes are one of the best ways to prevent algae because it dilutes nutrients like phosphate and nitrate.
Maintaining this maintenance regimen will ensure your aquarium stays clear and clean and your goldfish remain healthy.
For a more in-depth overview on cleaning a fish tank see our guide here as well as "12 Hacks to Keep Your Fish Tank Clean" here.
Feeding Your Goldfish
Goldfish will always greet you at the water surface. They always act like their starving. But don’t be fooled by their constant begging for food. Feed only what they’ll eat with several minutes and no more than twice a day. Over-feeding the fish also causes them to become obese, which is especially bad for fancy egg-shaped fancy goldfish varieties.
Goldfish will eat flakes, pellets and even frozen worms. Never leave uneaten food in the tank. It will just decay and foul the water. See our complete guide on feeding goldfish for more information on this topic.
Hopefully this guide on how to set up a goldfish aquarium has been helpful to you. Goldfish make great aquatic pets. They’ll even recognize you when you walk into the room. It’s not unusual for fancy goldfish to swim into their caretaker’s hand. Follow these recommendations and you’ll always have a clean aquarium filled with beautiful, fun, and healthy goldfish!