Goldfish

🐠 Goldfish (Carassius auratus)

Origin:

  • Domesticated in China over 1,000 years ago from wild carp.
  • One of the most popular aquarium & pond fish worldwide.

🌟 Varieties

  • Common Goldfish → long-bodied, hardy, pond-friendly.
  • Comet Goldfish → similar to common but with longer flowing tail.
  • Fancy Goldfish → rounder body, ornamental forms:
  • Oranda (head growth “wen”)
  • Ryukin (deep body, arched back)
  • Fantail & Veiltail (flowing double tails)
  • Ranchu & Lionhead (rounded, no dorsal fin)
  • Pearlscale, Bubble Eye, Telescope Eye, etc.

📏 Size & Lifespan

  • Common/Comet: 10–12+ inches, live 15–20 years (sometimes longer in ponds).
  • Fancies: 6–8 inches, live 10–15 years with good care.

🌊 Tank & Water Needs

  • Tank Size: Minimum 20 gallons for one goldfish, +10 gallons per additional. Bigger is better (they grow large!).
  • Water: Cooler temps preferred: 65–75°F (18–24°C).
  • Filtration: Strong filter required → goldfish produce a LOT of waste.
  • pH: Neutral to slightly alkaline (7.0–8.0).

🍴 Diet

  • Omnivores: High-quality goldfish pellets, supplemented with veggies (peas, spinach, zucchini) and treats (bloodworms, brine shrimp).
  • Avoid only feeding flakes → can cause buoyancy issues.

🐟 Behavior & Tankmates

  • Social, best kept in groups.
  • Peaceful but may outcompete smaller fish for food.
  • Tankmates: other goldfish (avoid tropical fish that need warmer water).

⚠️ Key Care Notes

  • Don’t keep goldfish in bowls → too small, poor oxygen exchange.
  • Provide strong aeration and regular water changes.
  • Watch for common issues: swim bladder problems, fin rot, ich.