Page 328 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

326 POND FISH: BREEDING

Reproductive cycle

The breeding triggers for coldwater fish are the rise Tubercles are
in water temperature and increasing day length that white, pimplelike
lumps that male
occur in spring. Spring also sees an increase in insect cyprinids, such as
Shubunkins, develop
life and aquatic crustaceans, providing food to bring when they are in
spawning condition.
adult fish into breeding condition and to sustain the The tubercles may help
fry. The breeding season is thus more prescribed than to arouse the female
when they are rubbed
in many tropical species, for whom rainfall rather against her body
than temperature is the most significant factor. Male’s sex during courtship.
tubercles
You can estimate when your fish are likely to breed by taking
regular measurements of the water temperature in the pond, A gravid female
since spawning typically occurs at around 68°F (20°C). This goldfish has a more
rounded body profile,
temperature ensures that the eggs develop at the correct rate: but she rapidly
at more than 9°F (5°C) above or below this figure, there is an regains her
increased likelihood that the fry will hatch with deformities, normal shape
after spawning.
because they will develop either too quickly or too slowly. She may spawn
Physical changes in the fish will also indicate that they are several times during
coming into breeding condition. For example, males of the spring and summer,
Cyprinidae family display white swellings called tubercles. producing several
In fish such as orfe, rudd, goldfish, and koi, the tubercles Belly swollen thousand eggs in total.
with eggs
appear on the gill plates and along the pectoral fins, while

Goldfish become sexually mature before they
are fully grown, and it is quite possible for
them to spawn when they are barely a year old. FROGS VERSUS GOLDFISH
In spring, frogs often visit garden ponds to spawn at the same time
that goldfish are breeding. On rare occasions, this results in frogs
accidentally killing goldfish. If a goldfish swims past a male frog, he
may grab the passing fish in the mistaken belief that it is a female
of his own species. If the frog grips the fish by its head, closing off
its gill covers, the goldfish will suffocate, since the frog’s mating
embrace lasts a long time, often for hours. There are casualties on
both sides, however, since goldfish will sometimes prey on frog
tadpoles in their pond. (They avoid toads, which are toxic to them.)

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