Care Guide for Fancy Goldfish – Housing, Feeding, and More

Fancy goldfish (Carassius aurantus) are gorgeous, selectively bred freshwater fish that can be found in a variety of colors, shapes and other characteristics. Unlike common goldfish with their single tails and streamlined physiques, fancy goldfish have flowy double tails and slow-moving, egg-shaped bodies that require special considerations. This care guide answers many of the questions we get most often about water piggies.

What Size Tank Do Fancy Goldfish Need?

Appropriate aquarium size can be a point of contention among goldfish owners, but in general, we recommend 20 gallons of water volume per goldfish, with at least 10 gallons added for every other goldfish. One goldfish will outgrow a 20-gallon aquarium in five to six years. This will mean that you will have to change the water frequently to keep the tank clean. Whereas if you house five or six goldfish in a 60- or 70-gallon aquarium, the tank maintenance schedule will be more manageable.

Goldfish tanks are bigger than ever, so make sure they have as much space as possible.

Consider the dimensions of your tank, in addition to the water volume. A squatter tank that has more water surface is better for goldfish. This is in contrast to a narrow, tall tank. In China where goldfish were first developed, they often use giant, wide bowls with lots of surface area because it provides the fish more swimming space and more gas exchange for increased oxygen. Bottom line: get the largest tank you can afford and make sure to regularly clean it.

Are Fancy Goldfish in Need of a Heater?

Cold water fish are goldfish because they can live at temperatures as low as 50-70 degrees Fahrenheit (10-21 degrees Celsius). This means that in a home with heating and air conditioning, there is no need to use a heater inside the aquarium because goldfish can live at room temperature. In fact, many people living in mild climates keep their goldfish in outdoor ponds year-round.

You may not need to heat your fish, but filtration is essential as goldfish are avid eaters and can produce a lot waste. Common choices include hang-on-back filters and sponge filters that have gentle flow and are easy to maintenance. You should ensure the filter creates surface agitation that increases oxygenation for your fish.

What Should I Feed My Fancy Goldfish?

They will eat less quality food and the tank will need more water changes. If you feed a “cleaner” diet with frozen foods or duckweed, the aquarium requires less maintenance, and the fish display more vibrant coloration. We like to give our goldfish frozen brine shrimp, high quality pellets, and Repashy gel foods.

Overfeeding your goldfish can lead to bloat, so consider giving them two small meals rather than one large meal per day.

Overfeeding is more common than underfeeding. So don’t spoil your goldfish by giving them too many meals, even if they begging for food. It is better to feed your goldfish smaller meals twice daily than one large meal per day. Goldfish are susceptible to bloating. The Internet says that floating foods should not be fed to goldfish as they can swallow too much air, which can cause them to bloat. However, we have been feeding floating foods for over a decade without any problems.

Why is my Goldfish tank cloudy?

There are many possible causes. It could be caused by beneficial bacteria rapidly reproducing because of increased fish waste. The best course of action is to patiently wait a week without making any drastic changes to the aquarium, and the bacteria cloud will eventually disappear on its own.

A water change is recommended if the water becomes cloudy due to too much particulate in the water. The filter cannot effectively remove the debris from the tank if it has become clogged up. We recommend getting easy-to-use water test strips and changing the water whenever the nitrates measure above 50 ppm. Try changing 30% to 50% of the water at a time, monitor how long it takes for the nitrates to reach 50 ppm again, and then develop a weekly or monthly schedule based on the results. Of course, as the fish get bigger, they will produce more waste, so it may be worth getting them a larger tank, moving them to an outdoor pond, or rehoming them to someone with more space.

To extend the time between water changes and provide greater enrichment for the fish, we like to use live aquarium plants as decor. We have an entire article on safe plants for goldfish, as they have a love for vegetables and will churn up substrate to search for food. The list mostly consists of rhizome plants like anubias and ferns that can be attached to driftwood and rock so that they can’t be easily uprooted.

Robust, easy-to-grow aquarium plants can help absorb nitrogen waste compounds and reduce your maintenance frequency.

Why are my Goldfish acting weird? Is it okay?

Goldfish are funny creatures that have their own unique personalities and idiosyncrasies, so what may be normal behavior for one fish may be quite abnormal for another fish. Therefore, we recommend that you check on your goldfish at least once a day when you feed them, so that you learn over time which ones are more lethargic versus overactive and what their habits are.

You should look out for signs of ich, such as large wens that have grown over the eyes and white spots. Make sure everyone’s getting along and the fish aren’t breeding too aggressively with each other. A successful tank will have an adequate temperature, pH, or nitrates monitoring at least once a week.

Because of this stigma, goldfish keepers are often discouraged from buying them. Goldfish are fairly hardy compared to more sensitive species, but you should still treat them with the same care you would give any other fish (e.g., regularly gravel vacuum the aquarium, service the filter, and test the water quality). The main caveats to remember are that a) they like cooler temperatures and b) they get much larger than most other pet store fish and therefore require a larger sized tank.