Pearlscale goldfish
Carassius auratus
intermediate careOverview
The pearlscale goldfish (Carassius auratus) is the round “golf ball” fancy, prized for its almost spherical body and domed, pearl-like scales that look like beads pressed into its sides. It reaches 13–18 cm and lives 10–15 years. That extreme rounded shape is charming but leaves little internal room, making the pearlscale highly prone to swim-bladder problems — careful feeding is the single most important part of keeping one well.
Tank & water
Give one pearlscale 75 litres (20 gallons), plus about 40 litres per extra fish. Priorities:
- No heater, stable warmth: pearlscales are cold-water fish that prefer a steady 18–23 °C as a delicate fancy.
- Smooth décor: their round bodies and domed scales damage on sharp objects — use rounded ornaments.
- Gentle, strong filtration: over-filter with a good external filter but keep flow soft, as they swim poorly.
Feeding
Pearlscales are omnivores, and their round shape makes diet management essential. Use a quality sinking goldfish food rather than dry floating pellets, and include blanched peas and soft vegetables to prevent constipation and floating. Feed small amounts once or twice a day, soaking pellets first, and remove leftovers. Keep water pristine with regular maintenance and water testing.
Tankmates
Keep pearlscales with other slow fancy goldfish — orandas, ranchu, lionheads, black moors and similar twin-tails. Faster fancies and single-tailed goldfish (comets, shubunkins) will out-compete these slow feeders, and nippy fish may damage their domed scales. They are not tropical community fish. A group of equally slow fancies in a spacious tank is ideal — plan numbers with how many fish in an aquarium.
A note on those pearl scales: if one is knocked off it usually grows back smooth rather than domed, so it never quite matches its neighbours again. That is one more reason to keep the tank free of sharp objects and boisterous tankmates. You will also see a crown-headed form (the “crown pearlscale” or hamanishiki) that adds a wen; it needs the same clean-water, sinking-food care, with extra attention to hygiene around the headgrowth.
Pearlscale goldfish — frequently asked questions
How big do pearlscale goldfish get?
Pearlscales reach around 13–18 cm but are famously round — almost spherical — so they hold a lot of body mass and waste for their length. They still need a large, well-filtered tank — see how big do goldfish get.
Do pearlscale goldfish need a heater?
No. Pearlscales are cold-water fish, though their extreme round body makes them delicate, so they prefer stable water around 18–23 °C. In most homes no heater is needed — see do goldfish need a heater.
Why is my pearlscale floating or sinking?
Their golf-ball body leaves little room for organs, making them very prone to swim-bladder problems. Feed a sinking food, soak pellets, and offer blanched peas. Never let a pearlscale gulp air from floating dry food.
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