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 does Fancy Goldfish require?

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.

When it comes to goldfish tanks and their needs, bigger is better. Give them as much space as you can.

You should also consider the dimensions of the tank. A squatter tank that has more water surface is better for goldfish. This is in contrast to a narrow, tall tank. Goldfish originated in China, where they were first introduced. They use large, wide bowls that have lots of surface area. This gives them more swimming space, and allows for more oxygen exchange. Bottom line, get the largest tank possible and keep it clean.

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.

While you may not need a heater, filtration is very important since goldfish are gluttonous eaters and therefore produce a lot of waste. Common choices include hang-on-back filters and sponge filters that have gentle flow and are easy to maintenance. Whichever filter you pick, make sure it creates good surface agitation to increase oxygenation for your goldfish.

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 love to feed our goldfish frozen brine shrimps, 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 tends to be more of an issue than underfeeding, so make sure not to spoil your goldfish too much (even when they beg like they’re starving). Also, feeding smaller meals twice a day is better than giving them a large meal once a day, since goldfish can be prone to bloating issues. There’s an Internet adage is that goldfish should never be given floating foods because they will swallow too much air and cause bloat, but we have regularly fed floating foods for more than a decade and never had problems with any of our fish.

Why Does My Goldfish Tank Have Cloudy Water?

It could be caused by several things. If the tank is newly set up or you added a lot of new goldfish recently, the cloudiness could be a bacterial bloom as the beneficial bacteria is rapidly reproducing in response to an increase in 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. It is a good idea to get water test strips. We suggest changing the water when the nitrates reach 50 ppm. You can change 30% to 50% of your water at once, then monitor the time it takes for the nitrates levels to rise again to 50 ppm. Then, you can create a weekly, or monthly schedule, based on these results. As the fish grow larger, they produce more waste. It may be worth buying a bigger tank, moving them outside, or giving them up to someone who has 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. Given that goldfish do have a taste for veggies and like to churn up the substrate while searching for food, we have an entire article covering the best plants that are safe for goldfish. 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 Is My Goldfish Acting Weird? Is it okay?

Because goldfish are quirky and have individual personalities, their behavior can be very different from one fish to another. 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. You need to make sure that everyone is getting along, and that the fish aren’t breeding aggressively. Monitor the temperature, pH, and nitrates at least once a week (even during the holiday season), and you’ll have a successful tank.

Goldfish keeping is frowned upon because of the stigma they carry. Beginners will often buy them and get the wrong advice. They may also end up in small water bowls with no water changes. 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.