Red Cap Oranda

Overview

Fancy Goldfish (Carassius auratus) are coldwater fish that have been selectively bred for centuries into many ornamental varieties (Oranda, Ranchu, Ryukin, Fantail, etc.). They are NOT tropical fish — they prefer cooler water and produce heavy bioload. Available in many colour and body forms.

Water Parameters

• Temperature: 18–24°C (64–75°F); they are coldwater fish — avoid prolonged temperatures above 26°C
• pH: 7.0–8.0 (slightly alkaline preferred)
• Hardness: 10–20 dGH (moderately hard; need minerals for health)
• Ammonia/Nitrite: 0 ppm — very sensitive to nitrogen cycle issues
• Note: Goldfish produce heavy bioload; excellent filtration essential

Tank Setup

• Minimum tank size: 100 litres for one fancy; 200+ litres for two; ponds for commons
• Substrate: Sand or fine gravel (they forage in substrate)
• Decor: Minimal; smooth rocks, driftwood; avoid small items they may ingest
• Filtration: Oversized — they are extremely messy and produce heavy bioload
• Note: Fancy varieties are poor swimmers; avoid strong currents

Diet

• Base: High-quality goldfish pellets (Hikari, New Life Spectrum)
• Treats: Blanched vegetables (peas, spinach, zucchini), frozen bloodworms (sparingly)
• Frequency: 2–3 small meals daily; they are always hungry
• Note: Overfeeding causes swim bladder issues and poor water quality

Temperament & Tank Mates

• Temperament: Peaceful, social, curious — they recognize owners
• Best companions: Other fancy goldfish of similar size and body type
• Avoid: Tropical fish (different temperature requirements); fast fish that outcompete them for food; loaches (may attack goldfish)
• Note: Keep same body type together — ryukins and orandas are compatible; don't mix with common/comet goldfish (different swimming speeds)

Breeding

• Difficulty: Easy; they breed readily in spring with temperature changes
• Process: Scatter eggs among plants; remove adults (they eat eggs)
• Note: Breeding in captivity is straightforward but fry require separate rearing

Common Issues

• Swim bladder disease — often caused by overfeeding or constipation; feed blanched peas
• Prone to columnaris, ich, fungal infections in poor water quality
• Protruding eyes in telescope/wakim types are prone to injury
• They can live 15–20+ years — consider the long-term commitment
• NOT tropical fish — keep in unheated or lightly heated aquariums
• Lifespan: 10–20 years with excellent care