Fantail goldfish are ornamental cold water fish, which were originally developed by the Chinese. This attractive and interesting goldfish type is an egg layer, and adults are in their prime from approximately 3 years of age. Fantail goldfish can be housed in indoor aquariums, but these fish are typically kept in outdoor ponds. Fantail goldfish in ponds begin to breed in spring and the enthusiast will notice both physical and behavioural changes in their fantails at this time. By closely observing the fish at the beginning of spring, the aquarist will easily be able to determine when their fantail goldfish are going to lay their eggs.
Watch your fantail goldfish closely at the end of winter to get a clear picture of their body shape and behaviour.
Observe your fantail goldfish closely during May and June, as the pond water begins to warm up. Female goldfish will typically fill out as their eggs begin to develop. Fantail goldfish however, tend to normally have egg-shaped bodies, which makes it more difficult to notice the plump appearance associated with gravid females.
Look at the females from above. A gravid fantail female will normally be rounder on one side. This is not too difficult to notice if the pond water is clear enough.
Observe all the fantails in your pond. Males will have a slightly more streamlined appearance, despite their overall egg-shaped body. Once you can identify the males, it will be easier to notice which females are carrying eggs. Look at the gill plates of the fish if you are experiencing problems with body shape. Male goldfish will possess raised, white-coloured tubercles on their gill plates, as the water gets warmer.
Look out for the first signs of spawning behaviour. Heavily gravid females will remain close to the spawning mop or aquatic vegetation in the pond.
Watch the behaviour of the fantail males. Males will know when the females are close to releasing their eggs and will begin to trail the female fish. The males will also begin swimming at and ramming the females, to induce them to lay. The male fish will ram females into the vegetation and against the sides of your pond. Once you see this behaviour, you can be sure that the female will release her eggs very soon.
Watch as the female begins to release hundreds of eggs into the water. The males will respond to the egg-laying process by spraying milt or sperm into the water. Once you observe this behaviour, you can confirm that your fantail female has started to lay her eggs.
Spawning mops consist of numerous strands of acrylic yarn to which goldfish eggs adhere. These mops are available from your aquatic dealer.