Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Carassius auratus auratus

Fancy Goldfish

Fancy GoldfishFancy Goldfish
Photos by Andy Rapson


Carassius: Latinization of , karass, karausche, European crucian carp auratus: From the words carassius--Latin of karass (common name for these fishes in Eurasia) and auratus, meaning gilded

General Notes:

Fancy goldfish aren't as hardy as standard goldfish. Their body shape and long finnage can be a source of numerous problems if they aren't cared for properly. Fancy goldfish are prone to having problems with buoyancy the risks can be minimised by selecting healthy active stock, keeping them in fairly shallow water of about 25cm (10in), feeding them away from the surface and using a diet high in fibre and avoid excessive use of prepared dried food.

People do keep fancy goldfish with other fish on occasion and because they don't immediately die their keepers often announce that I keep them with other fish and mine are 'happy' Fancy goldfish should really only be kept with similar fancy goldfish, this is because they are slow moving and not very agile they are easily bullied and out competed for food.

Most varieties of fancy goldfish do better in an aquarium rather than a pond in the UK. If kept in a pond our cold winters will lead to the extremities of the artificially long fins dying through poor blood flow and in turn it will lead to fin rot, they would also make easy prey items for herons, magpies and cats.

Although not essential using a heater is highly recommended, this can be used to make sure that the temperature doesn't fluctuate to much and to keep a minimum temperature of 18°C (65°F) which will keep the all important biological filtration working at a reasonable rate.

Obtaining fancy goldfish

Fancy goldfish are offered for sale in most aquarium shops but the are usually very low quality, indeed most would be turned away from a goldfish show because they were to different from the accepted judging standard. Things like missing fins where the anal fin for example should be paired or caudal fins which aren't divided, worse still where the fish have difficulty in swimming and just sit on the bottom  which is due to poor breeding. Very few high street fish stores sell good quality fancy goldfish, almost none will sell show quality fancy goldfish.

To obtain good quality fish which have been well bred and the fish are relatively problem free you will either have to find a reliable specialist retailer or join a goldfish society and by some young fish with good potential from a breeder. In either case the fish won't be cheap.


Housing fancy goldfish can also be problematic due to all the different recommendations. As with most fish bigger is better, of that there is no doubt. But With fish up to 10cm (4in) body size allow 45 litres (10 imp gall) per fish keeping in mind the minimum recommended tank size and that this doesn't mean that you could house one adult in a 45 litre tank.

Some varieties such as Orinda's which are capable of growing much larger than 10cm (4ins) will need housing in aquariums which are at least six times longer than the fish's length and double the width of the fishes length. Fancy goldfish aren't fast agile fish which need a huge amount of open swimming space, they can be kept quite content as long as the water quality is good and they have enough room to manoeuvre without getting trapped or banging in to things.

Food and feeding

All goldfish are omnivores with a strong leaning to vegetable matter. Adult fancy goldfish need a diet high in fibre and low in protein, young fish which are growing quickly need a diet high in both fibre and protein.

In  an experiment goldfish fry were split in to three groups and fed on three different diets, one group were fed on live baby brine shrimps, group two were fed 50% brine shrimps and 50% dried food and group three were fed dried food. After three weeks the first group had the best growth, group two with the mixed diet came second and the group fed on dried food had poor growth. However this changed after just three weeks when group two with the mixed diet grew fastest.

Ideal foods for goldfish are: duckweed, cucumber slices, skinless processed peas, algae, blanched spinach, occasional live or frozen daphnia, bloodworms and similar. Along with algae wafers and flake food which has been wet immediately prior to use so that it sinks.


When in breeding condition male goldfish like many of their relatives will develop tubercles which show as small white dots on their gill covers and surrounding area these are absent from the female.

All fancy goldfish despite their appearance are the same species. This means that all the different varieties are able to breed successfully with each other. In a mixed variety aquarium this might lead to undesirable offspring which have no commercial value and which you may end up stuck with.

Healthy well cared for fancy goldfish will come in to breeding condition on a regular basis without any special spawning triggers.  All goldfish are egg scatterers, the male usually drives the female and as she is being chased the eggs and sperm are released. The eggs are semi adhesive and will stick to plants. The adults are avid egg eaters so if you want to grow some fry you will have to quickly remove the parents after spawning. Due to their extreme body shape some fry will be born with very poor chances of survival, these individuals should be culled rather than letting them suffer a prolonged death.

Goldfish myths

  1. Goldfish will only grow to the size their tank allows. - False
    Poor care stunts goldfish not tank size.
  2. If a fancy goldfish is stunted due to its tank its internal organs will keep growing. - False
    Don't know who thought of that one but whoever it was doesn't know much about fish.
  3. Fancy goldfish need a high protein diet. - Only partly true.
    Only very young and rapidly growing fry need lots of protein.
  4. Goldfish only need a bowl and water to live happily. False.
    Goldfish are very hardy and adaptable which means they can survive for a time in poor conditions. They will die prematurely in such conditions and most definitely won't live happily in them.
  5. Fancy goldfish only live for a few years. - False
    Fancy goldfish are capable of living for many years with good care.

Information at a glance

pH: 7 - 8
dGH: 4 - 15
Temperature: 18 - 22°C (65 - 72°F)
Diet: Herbivore / Omnivore
Size: 25cm (10in), often less
Min tank size: 225 litres
Difficulty level: Intermediate
Aquarium type: Species
Swimming level: All levels

Distribution and habitat

distribution map for Fancy Goldfish

Origin: Captivity. Fancy goldfish are poorly adapted to wild living and if they managed to breed they would quickly revert to their wild form.

Habitat: Aquariums


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Carassius
Species: C. auratus auratus, (Linnaeus, 1758)

Common name:
Fancy Goldfish

Cyprinus thoracatus,
Cyprinus mauritianus,
Cyprinus maillardi,
Cyprinus langsdorfii,
Cyprinus gibelioides,
Cyprinus auratus,
Carassius pekinensis,
Carassius discolor,
Carassius coeruleus,
Carassius chinensis,
Carassius carassius auratus, Carassius auratus wui,
Carassius auratus cantonensis,
Carassius auratus