FREQUENTLY ASKED QUESTIONS

As a general guide for goldfish, we recommend 13-35 litres of water for one goldfish and 45-75 litres for two goldfish. Every 2.5 cm of goldfish requires 8 litres of water. Goldfish grow quickly and can produce a lot of waste.

There are several types to choose from, including canister, internal and undergravel filters, and all are suitable for use. Some have an integral motorised pump; others must be operated by an air pump. Visit your aquatic or pet retailer for advice about filter models to suit your size of aquarium and budget.

Distinguishing between sexes if difficult. One clue is during breeding (typically around spring) when mature male goldfish develop tiny white spots on their gill covers and pectoral fins. These are known as spawning tubercles — don’t mistake these spots for white spot disease.

Yes. Their sticky eggs are about 1.5 mm (one 16th of an inch) in diameter. They are normally scattered amongst fine-leafed aquatic plants. A female goldfish may lay several hundred eggs. The young fish hatch in a few days.

Consult a good goldfish book if you wish to breed them.

A goldfish’s colour may alter during its life. Young goldfish are typically olive-brown and gradually acquire their adult colours as they grow. Old goldfish, on the other hand, tend to pale with age and may eventually turn silvery white. Environmental conditions, such as an increase in water temperature or very bright light, may cause the goldfish colours to temporarily pale. Provided the fish appears healthy and is feeding normally, these colour changes should not give cause for concern.

Goldfish tend to nibble and uproot live plants, which is why artificial ones are popular. But if you want to try underwater gardening, the following two plants are recommended: Java fern (Microsorium pteropus) and Ludwigia (Ludwigia palustris).

Canadian pondweed (Elodea) is extremely popular and inexpensive, although goldfish tend to destroy it, so it will need replacing from time to time.

It is best not to do this. Although goldfish have a wide temperature tolerance, they prefer not to be kept under constant tropical conditions.

This depends largely on the size of your aquarium, notably its water surface area.

As a general guide, every 2.5 cm of tropical fish requires 3.8 litres of water. It is important to know the mature size of the fish in order to decipher how large they will get and how much water you will need.

NOTE: It is wise for beginners to understock the aquarium (e.g. half capacity) until they gain experience.

Guppies, platies and swordtails are recommended for beginners as they give birth to live young (hence they are known as ‘livebearers’). It is easy to tell the sex of a livebearer by looking at its anal fin (this is the unpaired fin situated between the fish’s belly and tail): the male’s anal fin point is pointed into a tube-shaped organ, whereas that of the female is normal fan-shaped. Livebearers will naturally breed in the community aquarium. Ensure the aquarium has lots of tall bushy plants so the babies can hide away (usually they hide at the water surface); otherwise they may get eaten.

Most other species of tropical fish are egg layers, and these are more difficult to breed in the community aquarium. You’ll need a separate tank and equipment to successfully breed egg-laying fish as the adults must be spawned in an aquarium by themselves. Most aquatic retailers stock a range of books explaining how to keep various types of egg layers.