|Sexual Dimorphism||Mature females fuller bodied. Mature males show breeding tubercles on gill plates & pectoral fins.|
|Maximum Size||20cm (7.9")|
|Temperature||Temperate: 10-22 deg C (50-72 deg F)|
|Water Parameters||Neutral to alkaline conditions preferred. pH: 7.0-8.0, dH: up to 25 degrees.|
|Compatibility||Fancy goldfish community.|
|Lighting||No special requirements|
The Ranchu is a selectively bred strain of goldfish, similar to the Lionhead but with a more strongly curved back. Domesticated goldfish date back to China’s Ming dynasty and Fancy goldfish have long been popular aquarium pets, although often as a first venture into keeping an aquarium. This is a mixed blessing, as there are far better choices for small aquaria than these big, messy fishes. Given appropriate housing and care, fancy goldfish can attain a large size and easily live for more than 15-20 years. The aquarium should be spacious and ideally around 1.2 metres long to allow room for 30cm adults to be comfortable. The length and width of the tank are much more important than the height in this respect.
Fancy goldfish grow quickly so it is best to provide them with the largest aquarium that you can from the outset to provide a much safe, stable environment for them. The larger the volume of water, the more stable it will be in terms of water chemistry and temperature. During the warmer months, these fish can be kept outside in raised water features suitably filtered and protected from predators. This can be a great way to provide extra room for your pets and they’ll benefit from the semi-natural conditions. Like any goldfish, fancies will benefit from a seasonal drop in temperature and this can be provided by either moving them indoors in late autumn, or positioning their aquarium in a room that experiences cool room temperatures during the winter. Fancy goldfish are notoriously messy fish; they are voracious eaters and continually stir up the substrate in their ongoing search for food. Such considerable amounts of waste can lead to water quality issues in smaller aquaria if not monitored very closely. Efficient filtration that can handle copius solids is essential, and weekly partial water changes are advised in order to keep nitrate to a minimum. The water should be well-oxygenated (of particular importance during warmer spells of weather) and this is easily achieved by the use of spray-bar returns from filters or the use of an air pumps. Various species of robust plants can be added to the aquarium, but these will likely require periodic replacement due to them being uprooted/eaten - something most goldfish keepers accept and allow their fish to take pleasure in. The substrate can consist of rounded fine gravel or sand, and decor can include smooth rocks and ornaments with no sharp edges. Ranchu are sociable creatures and should be kept in groups, either with their own kind or with other varieties of fancy goldfish. It is best, however, to avoid keeping the standard 'single-tailed' common goldfish alongside the fancy varieties as the common goldfish is a faster swimmer and may outcompete the fancies at feeding time. Several colour varieties of Ranchu are available, including black, blue, chocolate, red, red and white, red cap, white, yellow, and calico.
Due to their body shape, these fish need a high fibre diet and digestive problems are often the cause of buoyancy issues as transit times are compromised by convoluted digestive tracts. Goldfish also tend to swallow air in their rush to feed which also leads to problems which are best avoided by the use of sinking foods. These can be in the form of pellets, sticks or flake presented beneath the water surface. Frozen foods or live foods such as bloodworm, Mysis, and Daphnia will provide fibre and can be fed extensively to individuals displaying issues that are often categorised as Swim Bladder Disease. The opportunity to browse on aquatic plants will help to ensure gut health.
Well-conditioned fancy goldfish will often spawn in the home aquarium. Female fish will be noticeably rounder bellied when full of eggs, and the male fish will develop spawning tubercles (tiny raised bumps) on the gill plates and pectoral fins. A large, slightly cooler water change is often enough to trigger ready pairs into spawning. As the temperature slowly rises back up to its usual level, the male will pursue the female around the aquarium, but generally in a non-aggressive manner. This courtship ritual may last more than a day before spawning commences, and the colours of the fish often intensify at this time. The male fish will nudge the female into the fine-leaved plants (or spawning mops), where she will then scatter eggs which the male simultaneously fertilises. Spawning can last for a number of hours, and several thousand adhesive eggs may be scattered over the plants/spawning mop. The adults will be hungry and will start to devour as many eggs as they can find, so are best moved to another aquarium. The eggs take 4-5 days to hatch, depending on water temperature. Young fancy goldfish are often brown in colour (like their ancestors) and it can take up to a year before full colouration becomes apparent. Fancy goldfish often produce young that differ from their parents - high quality fish that show the best attributes of their breed are normally in the minority, hence the differences in price and quality between fish.