Goldfish Wellness: A Crash-Course
A Quick & Dirty Guide to Preventing & Treating Illness in Goldfish
© Ren Weeks
Goldfish are one of the most commonly kept species in the aquarium fish trade. Hardy, attractive, diverse, and capable of surviving a wide range of conditions, they are bred, sold, and kept on a massive scale. Unfortunately, they are also bred, sold, and kept poorly on a massive scale due to their high demand, low cost, and "throw-away" status, resulting in a variety of health conditions stemming from poor breeding, poor care in stores, and improper husbandry at home. As a result, there are several common health conditions that are almost as common as the goldfish itself. This guide serves as a "crash course" in identifying, treating, and most importantly preventing such ailments using a wellness-based husbandry paradigm. This is for keepers who not only want to treat a problem, but remedy the (often causative) husbandry and prevent future problems.
Promoting WellnessWater Keepers
Fish keeping is less about keeping fish than it is about keeping water - or rather keeping a stable, balanced aquatic environment. The primary cause of most fish illnesses stem from inappropriate water conditions, and because goldfish produce more waste and require different water conditions than many tropical species we (incorrectly) model their care off of, water-quality related conditions are almost always the cause of health problems in goldfish. The best way to keep your goldfish well is to take good care of its environment. This means, on the most basic level:
- Only keep goldfish in a filtered, cycled aquatic environment. Goldfish, unless in a very under stocked tank require a GPH at least 10x that of their gallonage. All goldfish tanks must also be cycled to create a healthy population of waste-nitrifying bacteria; without this, even well filtered tanks will experience dramatic hikes in ammonia and nitrate caused by the high waste output of the species. Remember, filters mechanically trap waste but do not eliminate their chemical products.
- Goldfish MUST have weekly water changes - yes even in a cycled, filtered tanks. Goldfish produce a large amount of fecal waste due to their omnivorous and often vegetation-intense diet. They are big fish with big appetites, and thus, they are big waste producers. Even in a well-filtered and cycled tank, you MUST gravel-vacuum to reduce loose waste matter, or you will suffer water quality issues and a build-up of unhealthy bacteria as waste decomposes. It is suggested to change 10-25% of the water in your goldfish tank weekly depending on the stocking and filtration.
- Stock sparingly. Goldfish can grow to be extremely large - up to a foot in "fancy" varieties and sometimes in excess of 2ft in single tail or "common" varieties. They have high activity, high waste output, and high oxygen needs. While there is no magical "inches per gallon" rule as some may have you to believe, it is generally accepted that, with some variability based on surface area, temperature, and filtration, you still want at least 2g per inch of body length for fancies and 3-5g per inch of body length in commons. This means a full grown fancy goldfish at bare minimum should have a 20g tank (larger with the broadest surface area available if possible) and commons upwards of 50g or more per fish.
- Oxygenate thoroughly. Cold water holds more dissolved gasses than warm water, and as a result, goldfish are adapted best for waters with high oxygen content. Surface area and surface area agitation are both very important components for water oxygenation. Bubblers do not actually add oxygen to a tank; while some bubbles may break up and disperse before reaching the surface, most merely create surface agitation. A bubbler is a good tool for creating additional surface agitation, which incorporates dissolved gasses into the water, but a strong filter current and a broad surface area are both crucial. Select for wider tanks over tall (ie. a 40g breeder over a 40gH) and don't shy from powerful filtration or extra bubblers.
- Stay cool. Goldfish survive a wide range of temperatures, but as cold water fish, do best at temperatures from the mid 60's to low 70's. Keeping goldfish at tropical temperatures (76-84) not only makes it harder to meet their oxygen needs, but also puts chronic stress on the animal that can result in health problems.
One of the second leading causes of poor health in goldfish is poor diet. Omnivores can eat just about anything - but it doesn't mean they should! Below are some helpful hints for diet and nutrition to optimize your goldfish's health.
- Forget the flakes. Goldfish flakes, though a popular staple in the day of fish bowls, are a poor choice of diet for goldfish. They contribute to swim bladder disorder & constipation in fancy goldfish due to their dryness and tendency to swell in the gut. As less concentrated nutrition, they're also a poor choice for commons, which need a large amount of high quality food to accommodate their rapid growth.
- Avoid floating pellets and freeze-dried foods; these products hold air which can lead to bloating and pressure on the swim bladder. Fancy goldfish in particular should only be fed sinking pellets, but this is beneficial to commons/single tails as well.
- Quality is job #1 - don't skimp on food quality in pursuit of cheaper prices, or your fish will pay in the long run. Goldfish foods that are high in soy, wheat, and preservatives are not an ideal diet and can lead to bloating and constipation. A quality goldfish pellet should have a good balance of high quality plant and animal proteins. We suggest New Life Spectrum and similar quality brands.
- Keep it fresh. One of the best things you can do for a goldfish's diet is incorporate fresh and whole foods. Steamed dark leafy greens, aquatic plants, bits of citrus and vegetables, frozen invertebrates, and similar products should be a supplement to your goldfish's diet.
- Consider home-made diets. Many goldfish keepers, particularly of fancy goldfish, make their own foods using a gelatin base. These gel-based foods are easier for goldfish to digest and often have better ingredients than commercially available foods. Check out Koko's Goldfish Forum for great info on making home-made gel diets!
- Don't over-feed. Over-feeding puts stress on the swim bladder and also causes more waste output, resulting in declining water quality.
While goldfish are a gregarious social species, they are best kept with their own kind. This means single tail varieties with other single tails, fancies with other fancies, and fancies with extreme anatomy that inhibits competition - such as pearl scales - with others of their own breed. A few species, such as the dojo loach, are appropriate goldfish tank mates. But most species are not. Here are a few common "problem species" often kept with goldfish:
- Common Pleco - marketed as an essential to any goldfish tank to manage algae (a falsehood), these fish can grow to over 18" in length and are notorious for damaging the eyes and slime coat of goldfish.
- Chinese Algae Eater - this hardy species is sold to tropical and coldwater keepers alike, again under the assumption that it will eat algae. The species is not a true algae eater at all, but rather an omnivorous scavenger and opportunist that will prey on slow fish like the fancy goldfish.
- Betta - many folks think that goldfish can be kept in bowls, and that a good bowl buddy for their goldfish is a betta. Obvious problems with bowl keeping aside, the betta is likely to harm the colorful, slow moving, long-tailed fancy goldfish, and may harm or be harmed by a common/single tail goldfish.
- Koi (for fancies) - Koi are an acceptable species to mix with single tails in a pond environment, but many folks try to keep koi in their home aquarium or pond with fancy goldfish. Koi are large, powerful fish and can damage delicate fancy goldfish with the simple pushing nudging common of competition in the species.
Common AilmentsDisease & Condition Profiles
Below is a guide to the five most common conditions that afflict goldfish, their causes, and their treatments. This is a basic, outline-form introduction to goldfish health conditions as a launching point for further research on the condition. Please always research and ask advice before diagnosing and treating an ailment for the first time.
- Ammonia Poisoning
- Causes: Unsuitable water change schedule, overstocking, undersized tank, uncycled tank
- Symptoms: Gasping, rapid gill movement, red gills, clamped fins, listing, sudden blackening of fins or gill covers, death
- Treatment: Perform significant water changes until ammonia is below detectable levels. Add 1/2 tbsp aquarium salt per 5 gallons. Aerate water thoroughly. In severe cases of ammonia burn (blackened fins), adding a slime coat promoting product may ease irritation.
- Prevention: Only keep goldfish in a cycled, filtered, appropriately stocked tank; perform regular water changes.
- Fin Rot
- Causes: Poor water quality, bacterial infection
- Symptoms: Loss of finnage, blackened or bloodied edges to fins
- Treatment: Pristine water quality, 1/2 tsp salt per gallon, slight bump in tank temperature. Severe and rapidly progressing cases may require a broad-spectrum anti-biotic.
- Prevention: Maintain high standard of water quality.
- Causes: Protozoal parasites; often brought on by stress or temperature fluctuations.
- Symptoms: Fine white dots covering fish, flicking against ornaments and gravel, flashing/darting, clamped fins
- Treatment: Raise temperature gradually to ~ 80*F, add 1/2 tsp aquarium salt per gallon, treat with a medication geared towards protozoans such as Coppersafe, Rid-Ich, General Cure, etc. as directed.
- Prevention: Quarantine all new fish, reduce causes of stress, avoid sudden temperature fluctuations.
- Internal Parasites
- Causes: Often present in all fish due to breeding/store conditions; typically asymptomatic unless stressed
- Symptoms: White stringy feces, flashing and darting, flicking against ornaments and gravel, weight loss, red swollen vent
- Treatment: Raise temperature gradually to ~ 80*F, add 1/2 tsp aquarium salt per gallon, feed an anti-parasitic food or soak food in anti-parasitics, treat with a medication geared towards internal parasites such as Praziquantel or Paracide.
- Prevention: Quaratine all new fish, reduce causes of stress.
- Swim Bladder Disorder
- Causes: Anatomical defect, injury, infection, parasites, constipation, poor water quality
- Symptoms: Floating on side, sinking to the bottom, difficulty orienting, rolling while swimming
- Treatment: Pristine water quality, high quality diet. If caused by pathogen, appropriate antibiotic or anti-parasitic treatment. Severe cases caused by anatomy may require slings and weights to maintain goldfish's orientation.
- Prevention: Maintain high standard of water quality. Feed low-inflammatory, low-constipation foods such as a gel diet. Avoid purchase of fish with extreme anatomy & do not mix fancies with single tails. Quarantine new fish.
The majority of health problems in goldfish are directly correlated to poor husbandry practices, whether inadvertent or outright negligent. Poor water quality resulting from unsuitable tank size, stocking, filtration, or cleaning schedule is the cause of many a goldfish's ails. A low quality diet or dangerous tank mates pose equally dire risks. By keeping your goldfish with others of its kind in a clean, appropriate environment and feeding a healthy diet, you can avoid most health problems. An ounce of prevention is worth a pound of cure; taking a proactive stance on goldfish wellness will ensure that you can enjoy your fishy friend for years to come.