Goldfish are one of the most popular pet fish, not only for their stunning colors and shimmering scales, but also for their high intelligence. With proper care, they can even recognize their keepers. Originated in China during the Tang Dynasty, which spanned from the 7th and 10th centuries, these creatures were first introduced to Europe in the 17th century and North America in the 19th century after being artificially bred for generations. While goldfish might seem like the entry-level, the “starter pack” for aquarium companions, they take more than a bowl and some fish flakes to keep them happy and healthy. Here's your crash course on goldfish care, so you can better care for your goldfish, whether you're a novice or an experienced fish keeper.
Common Goldfish vs. Fancy Goldfish
There are over a hundred breeds of goldfish, but they can be roughly divided into two categories - common goldfish and fancy goldfish. Common goldfish are the classic single-tailed goldfish you often see in ponds. They are streamlined, fast-swimming, and can grow REALLY big, up to 12 inches! Comets and Shubunkins also fall into this category.
On the other hand, think of fancy goldfish as the designer breeds of the goldfish world. They come in a variety of shapes and sizes, with double tails, bulging eyes, funky head growths, and a whole lot more genetic quirks. Examples include Orandas, Ranchus, Ryukins, and Pearlscales.
Goldfish Lifespan and Size
With proper care, goldfish can live surprisingly long. Common goldfish can live for 10-15 years, and some have even reached over 20. In contrast, fancy goldfish typically have a shorter lifespan, averaging around 5-10 years. Size-wise, common goldfish can grow quite large, often exceeding 12 inches in length, while fancy goldfish tend to stay smaller, reaching about 6-8 inches in length.
Setting Up Goldfish Habitat
Tank Size
Goldfish aren’t meant for those tiny bowls you often see in movies. They actually need enough room to swim and thrive, depending on the species and their adult size. For instance, a single common goldfish requires a minimum of 75 gallons of water, and you’ll need to add 50 gallons for each additional common goldfish. On the other hand, a single fancy goldfish requires a minimum of 20 gallons, with an additional 10 gallons for each extra fancy goldfish. Keep in mind that these are the bare minimum. The more space you can provide, the better it is for your fish.
Filtration
Goldfish are messy eaters and produce a lot of waste, so having a robust filtration system is non-negotiable. Invest in a filter that is rated for a tank size larger than your actual tank volume. Options include:
- Hang-on-back (HOB) Filters: Suitable for smaller tanks.
- Canister Filters: Provide superior filtration and are ideal for larger tanks.
- Sponge Filters: A good option for breeding tanks or for delicate fancy goldfish as they provide gentle filtration.
Make sure your filter has mechanical, chemical, and biological filtration to effectively remove debris, toxins, and harmful bacteria.
Temperature
Goldfish are cold-water fish that prefer temperatures between 68-74°F (20-23°C). While they can tolerate slight variations, extreme fluctuations can stress them and make them more vulnerable to disease.
A temperature controller like INKBIRD ITC-306A can be a great addition for your goldfish tank, as it continuously monitors and automatically control water temperature, helping to maintain a stable and healthy habitat. This is especially beneficial in climates with significant temperature swings.
Water Quality
Keeping your water quality in check is crucial. Make it a habit to regularly test your water with a liquid test kit to keep an eye on these important parameters:
- pH: 6.5-7.5
- Ammonia: 0 ppm
- Nitrite: 0 ppm
- Nitrate: Below 20 ppm
Substrate
Bare-bottom aquariums are easiest to clean, preventing detritus buildup, and are suitable for fancy goldfish, which often have limited vision. Alternatively, you can also use smooth gravel or sand as a substrate to keep goldfish safe from getting hurt, but be prepared to vacuum it regularly to prevent the formation of anaerobic pockets. What’s more, it's best to avoid using small gravel that goldfish may accidentally ingest.
Decorations and Plants
Choose decorations that are smooth and free of sharp edges to prevent injury. Live plants offer numerous benefits, including oxygenating the water and providing hiding places. Hardy plants like Anubias, Java Fern, and Hornwort are good choices. Avoid delicate plants that goldfish are likely to eat.
Lighting
Goldfish don't require specialized lighting. Standard aquarium lighting is sufficient. A light cycle of 10-12 hours per day is recommended to promote healthy plant growth and regulate your fish's natural rhythms.
Goldfish Care Routine
Feeding
Goldfish are primarily omnivores and can be fed a sinking pellet diet containing approximately 30% protein. A balanced meal plan should feature a combination of high-quality flakes or pellets, supplemented occasionally with blanched vegetables like peas or spinach, along with treats such as bloodworms or Daphnia. To add variety, you can also introduce live or frozen options like brine shrimp and krill. It's best to feed your goldfish once or twice daily, offering only what they can consume in 2-3 minutes to avoid overfeeding, which can harm their health and water quality.
Water Changes
Perform partial water changes of 25-50% on a weekly or bi-weekly basis, adjusting based on your tank size and the number of fish you have. Plus, use a gravel vacuum to remove debris from the substrate. The most importantly, always use a water conditioner to remove chlorine and chloramine from tap water before adding it to the tank.
Disease and Treatment
Even with the best care, goldfish can sometimes get sick, often caused by poor water quality or stress. Here are a few common goldfish diseases and how to treat them:
Ich (White Spot Disease): Small white spots on the body and fins. Treat with medication containing malachite green or copper sulfate.
Fin Rot: Ragged or deteriorating fins. Treat with antibiotics.
Swim Bladder Disorder: Difficulty swimming or maintaining buoyancy. Often caused by poor diet or constipation. Adjust diet and ensure proper water parameters.
Fungal Infections: Cotton-like growths on the body. Treat with antifungal medication.
Beyond that, prevention is key. To avoid disease, focus on maintaining high water quality, offering a well-balanced diet, and regularly checking your fish for any signs of illness. It's also a good idea to quarantine any new fish before introducing them to your main tank to prevent the spread of potential diseases.
FAQs
How long do goldfish live?
Goldfish can have surprisingly long lifespans with the right care. Common types like Comets and Shubunkins often live between 10 to 15 years, and some even make it to 20 years or more. Although fancy goldfish typically have shorter lives, they can still thrive for 5 to 10 years if well cared for.
How big can goldfish get?
This depends on the variety and environment. Common goldfish, when kept in a spacious pond, can grow to be 12-16 inches or even larger. In contrast, fancy goldfish, which are usually kept in aquariums, tend to grow to about 6-8 inches in length. Remember, a small bowl will severely stunt their growth and lifespan, leading to health problems.
What fish can live with goldfish?
This is a tricky question. Goldfish are cold-water fish and prefer temperatures lower than many popular tropical fish. Also, goldfish produce a lot of waste, requiring a strong filtration system that some fish might not tolerate. Ideally, goldfish should be housed with their own kind, but if you want to add other fish, consider options like White Cloud Mountain Minnows, which can handle cooler temperatures, or Hillstream Loaches, which enjoy oxygen-rich water and help manage algae growth. Just be cautious to avoid smaller fish that could become a meal for your goldfish or species like betta fish that might nip at their fins.
How often to feed goldfish?
Goldfish should be fed once or twice a day, offering only as much food as they can consume in 2-3 minutes. They don't have stomachs and are always hungry, so it's up to you to control their portions.
Do goldfish have teeth?
Goldfish do not have teeth in their mouths. Instead, they have pharyngeal teeth located in their throat, which they use to grind food before swallowing.
Why is my goldfish turning black?
A goldfish turning black can happen for a few reasons. One common cause is ammonia burns, which occur when water quality is poor and ammonia levels rise, leading to black patches, especially on the fins. This situation needs quick action to improve water conditions. Additionally, if a goldfish has experienced an injury or illness, it might develop black spots as part of the healing process. Genetics also play a role; certain varieties, like Shubunkins, naturally have black markings or can change color as they grow. Lastly, too much sunlight can stimulate melanocytes in the skin, resulting in increased black pigmentation.
