Our Guide To Keeping Calico Ranchu Goldfish

1. About Fish Species:

   • Scientific name: Carassius auratus (Ranchu variety)
   • Common name: Calico Ranchu Goldfish
   • Family: Cyprinidae
   • Origin: Selectively bred in China and Japan from wild Prussian carp
   • Adult length: 12–15 cm (4.5–6 inches)
   • Lifespan: 10–15+ years with proper care
   • Diet: Omnivore
   • Care Level: Moderate
   • Temperament: Peaceful

2. Tank Setup:

   • Tank size: Minimum 75 L for the first Ranchu, plus ~40 L for each additional fish.
   • Layout: Open swimming space with soft sand or rounded gravel. Avoid sharp decorations that may damage their delicate fins or wen (head growth).
   • Plants: Use hardy, goldfish-safe plants like Anubias, Java Fern, or Hornwort. Expect occasional nibbling.
   • Oxygenation: Maintain good aeration with an air stone or spray bar.

3. Water Parameters:

   • Temperature: 18–22 °C (fancies prefer the warmer end of the goldfish range).
   • pH: 7.0–8.0, stable and moderately hard.
   • Quality: Ammonia and nitrite at 0 ppm, nitrate < 20–40 ppm. Large, frequent water changes are essential due to their high waste output.

4. Filtration and Water Flow:

   • Filtration: Use a filter rated for at least 6–10× the tank volume per hour. Ensure strong biological filtration.
   • Flow: Keep water movement gentle—Ranchus are slow swimmers and can struggle in strong currents.

5. Diet:

   • Staple: High-quality sinking goldfish pellets or gel foods formulated for fancy goldfish.
   • Veg: Offer blanched peas, spinach, kale, or courgette regularly for fibre and digestion.
   • Treats: Frozen or live brine shrimp, daphnia, or bloodworms (in moderation).
   • Tips: Avoid floating foods to reduce risk of gulping air and buoyancy issues.

6. Tank mates:

   • Best: Other fancy goldfish with similar swimming speeds.
   • Possible: Large, peaceful coolwater fish such as Dojo Loaches in very large aquaria.
   • Avoid: Fast single-tail goldfish, fin-nippers, or small tropical fish that may be eaten.

7. Behavior and Compatibility:

   • Behavior: Gentle and slow-moving; may be outcompeted for food by faster tank mates.
   • Social: Enjoys the company of its own kind; best kept in groups of at least two or three.
   • Notes: Due to their rounded body and head growth, Ranchus are less agile and require a calm, obstruction-free environment.