🐠Goldfish: gear and buying guides

The goldfish is a social, greedy cyprinid that easily reaches 20 to 30 cm as an adult, a far cry from the fishbowl cliché. It lives in unheated cold water and requires at least 100 L for a single fish, ideally much more since it should be kept in groups. As a heavy waste producer, it calls for oversized filtration and regular water changes.

Profile : 20 to 30 cm as an adult, 100 L minimum per fish, cold water at 18 to 22 °C with no heater.

Goldfish gear, family by family

• 🍖 Food

  A big-appetite omnivore: sinking cold-water pellets, supplemented with blanched vegetables and frozen foods. Split meals into small portions to limit digestive issues and water pollution.

• 🧴 Care & grooming

  Goldfish produce a lot of waste: plan a filter turning over 4 to 5 times the tank volume per hour and a 20 to 30 percent water change every week. Monitor nitrites and nitrates with regular test kits.

• 🎾 Toys & enrichment

  Choose sturdy plants such as anubias or vallisneria, as goldfish uproot and nibble everything. Smooth driftwood and rounded stones provide exploration areas without damaging their fins.

• 🏠 Bedding & habitat

  Allow 100 L for the first fish and roughly 50 L per additional one, in a tank that is longer than it is tall. Sand or rounded gravel works well, with a lid or hood to limit evaporation.

• 🧳 Travel & safety

  Transport it in a bag filled one-third with water and two-thirds with air, secured in an insulated cooler. Then acclimate for 20 to 30 minutes to equalize temperature before releasing it without the bag water.

• 🧰 Accessories

  A powerful external filter, a wide net and a gravel vacuum are essential; a heater is unnecessary. Expect an initial equipment budget of around 150 to 300 euros for a 100 to 200 L tank.

Guides to read

• 60-litre aquarium kit: the full beginner budget with no nasty surprisesBedding & habitat

  How much does a 60-litre aquarium kit really cost? The full start-up budget, item by item: equipped tank, substrate, decor, water tests and consumables.

• Nano shrimp tank: the essential equipment to start off rightBedding & habitat

  What equipment does a nano shrimp tank need? Volume, gentle filtration, the right substrate and a full budget: the complete checklist for keeping Neocaridina.

• Betta tank of 20-30 litres: the ideal setup, step by stepBedding & habitat

  How do you set up a 20 to 30 litre betta tank? Low-flow filtration, heating, resting plants and a lid: the ideal setup explained in detail.

• Garden pond for goldfish: volume, equipment and budgetBedding & habitat

  How do you build a garden pond for goldfish? Minimum volume, frost-free depth, filtration and predator protection: the complete guide with budget.

• RO units and reverse osmosis water in aquariums: who actually needs it?Care & grooming

  Is reverse osmosis water essential for an aquarium? Find out who really needs an RO unit, how to remineralize and what budget to plan (unit or jerrycan).

• Water conditioner and starter bacteria: essential or just marketing?Care & grooming

  Water conditioner and starter bacteria: what do they actually do? Chlorine, heavy metals, faster cycling: what to buy and what to skip.

• Fertilizer and CO2 for aquarium plants: start simple, skip the lab setupToys & enrichment

  Do aquarium plants need fertilizer and CO2? The simple starter method: liquid fertilizer, easy plants, and when injected CO2 actually becomes worthwhile.

• Driftwood and rocks for aquariums: which ones are safe for your fish?Toys & enrichment

  Which driftwood and rocks are safe in an aquarium? Tannin-releasing woods, limestone rocks to avoid, the vinegar test and preparation: the complete guide.