Goldfish

Environment

It needs a large volume of cold water: allow 50 to 100 liters per fish, i.e. 100 liters minimum for a pair, and no heater. The ideal temperature is between 18 and 22°C, pH 6.5 to 8. Powerful filtration is essential as it produces a lot of waste; it uproots plants, prefer robust species or potted ones.

Feeding

Omnivorous, it accepts specific goldfish pellets, blanched vegetables (spinach, zucchini, peas) and frozen prey. Avoid overfeeding, common with this voracious species. Sinking foods limit air ingestion by round-bodied varieties.

Health & common diseases

The goldfish is susceptible to white spot disease (ichthyophthirius), fin rot, fungal infections and dropsy (swollen abdomen, raised scales). Symptoms to watch for include white spots on the body, frayed or torn fins, cottony patches, and lethargic behavior. Prevention involves clean water (regular 20-30% weekly changes), a varied diet without excess, sufficient volume (minimum 50L per fish), and good oxygenation to limit stress and pathogens.

Tips & tankmates

The fishbowl is to be absolutely avoided: too small, unfiltered, it condemns the animal to a brief and painful life. Do not associate it with tropical fish, as its cold water needs are incompatible. Cold-water companions such as other goldfish or hornwort suit it better.

Sources

• Carassius auratus — Wikipédia
• Carassius auratus — FishBase