What are the minimum conditions for keeping a goldfish?

The goldfish Carassius auratus is a freshwater fish that is commonly found in aquariums but it is unfortunately very rare that it is kept in satisfactory conditions.

Goldfish are very demanding in terms of breeding and they should not be recommended for beginner aquarists. Their genetic selection pushed to the extreme makes them very fragile, their digestive physiology is very restrictive, they are big water polluters…

In good conditions, a goldfish can easily live for around fifteen years, otherwise, it will struggle to reach 5 years.

Shape of the aquarium

The shape of the aquarium should be rectangular (or square).

No species of fish is suitable for a ball aquarium, because whatever its volume of water, gas exchanges (oxygen / carbon dioxide) are very poor (low water surface in relation to the volume).

It is recalled that ball aquariums are prohibited (rightly) in certain European countries such as Italy.

Volume of the aquarium

The minimum volume required for a goldfish is 50 liters per individual. For a couple, you therefore need 100 liters of water.

For large specimens of goldfish, this volume should be increased to 100 to 200 liters of water per individual.

For common goldfish, when possible, it is even preferable to keep them in an outdoor pool (even in winter).

Floor

The floor of the aquarium should be covered with sand fine(Loire sand or Quartz sand). Gravel or large pebbles should be avoided as organic matter may accumulate in the gaps.

Filtration

Aquariums need a filter to collect droppings and detoxify the ammonia excreted by the fish. Goldfish being large polluters, the filter must be of a substantial volume with good mechanical and biological filtration.

Group

Goldfish are gregarious animals (which live in groups). It is advisable to maintain at least 2 specimens in order to reduce stress and the appearance of overly stereotyped behavior.

Feeding

Goldfish are omnivorous, meaning that their diet must include foods of both plant and animal origin. They cannot be satisfied with flake or pellet food. To feed them correctly, refer to this section: How do I feed my goldfish in an aquarium?