Shubunkin Goldfish (Carassius auratus)

The Shubunkin Goldfish (Carassius auratus) is the classic calico goldfish — a single-tail variety with translucent scales over a vibrant patchwork of orange, red, blue, black, and white. Beginner-friendly, peaceful, and incredibly long-lived, Shubunkins are equally at home in a large indoor aquarium or a backyard pond. These are 2–3" juveniles that will grow rapidly with proper care.

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Care Guide

• Tank size: 30 gallons minimum for a single juvenile; 55+ gallons long-term, or a pond. Shubunkins are messy, fast-growing, and need space to swim.
• Water parameters: 65–72°F (coldwater — no heater needed in most homes), pH 6.5–8.0, GH 5–19. Tolerates a wide range as long as the water is clean.
• Filtration: Over-filter. Goldfish produce a heavy bioload, so target 6–10× tank turnover per hour with strong mechanical and biological filtration.
• Substrate: Sand or smooth-rounded gravel large enough that fish can't swallow it. Shubunkins love to sift the substrate.
• Diet: Omnivore. Feed a high-quality sinking goldfish pellet as the staple, supplemented with blanched veggies (zucchini, peas, spinach) and the occasional bloodworm or daphnia.
• Water changes: 25–30% weekly. Goldfish are nitrate-sensitive — keep nitrates under 40 ppm.
• Lifespan: 10–20+ years with good care. They commonly outlive cats and dogs.

Specifications

Compatibility

• Good tankmates: Other single-tail goldfish (common, comet, sarasa), koi in a pond setting, white cloud minnows in cooler tanks.
• Avoid: Tropical community fish (water-temperature mismatch), fancy goldfish (Shubunkins outcompete slower fancies at feeding time), aggressive or fin-nipping species, and small inverts like cherry shrimp (which will be eaten).
• Plants: Goldfish will graze on most aquatic plants. Stick with hardy options like Hornwort, Anubias attached to driftwood, or Java fern — and accept some nibbling.

Recommended Foods & Supplies

• API Goldfish Pellets — complete daily staple food.
• Hornwort — fast-growing, goldfish-tough plant that doubles as a snack.
• Water care & conditioners — clean water is everything with goldfish.
• Filter media — heavy bioload means heavy filtration.

FAQ

Can I keep one in a 10-gallon tank?
Not long-term. Shubunkins grow fast and big. A 10-gallon is fine as a temporary grow-out, but plan to upgrade to a 30+ gallon (or pond) within the first year.

Will the colors change as it grows?
Yes — calico patterns shift considerably as Shubunkins mature. Juveniles often deepen and develop more blue and black over their first 1–2 years.

Are they pond fish or aquarium fish?
Both. Shubunkins are one of the best beginner pond fish in mild climates and thrive in large indoor aquariums year-round.

What size will I receive?
Approximately 2–3 inches at pickup. Each fish is unique — patterns and exact size will vary.