Goldfish Tank Setup Guide: Size & Filtration Basics

Proper environmental preparation is essential for keeping goldfish healthy long-term. Here's a summary of the basic points from tank selection to setup procedures.

Choosing Tank Size

Goldfish include varieties that grow quite large, so choosing a larger tank is fundamental.

• Small (up to 30cm tank): Limited to 1–2 small Wakin. Water quality becomes unstable easily
• Medium (60cm tank): 2–4 Ryukin or Telescope Eye. The most manageable size for beginners
• Large (90cm and above): Multiple Ranchu or Wakin. Large water volume keeps water quality stable
• Water lily bowls/outdoor containers: Suitable for Wakin and Comet. Watch temperature management in summer and winter

As a guideline, aim for 20–30 liters of water per fish.

Types of Filtration Systems

Goldfish produce a lot of waste. Powerful filtration is essential for long-term keeping.

• Hang-on-back filter: High filtration capacity, standard for goldfish keeping. Best for 60–90cm tanks
• Canister filter: Quiet operation, suitable for large tanks. Watch for oxygen deficiency
• Under-gravel filter: Excellent biological filtration. Requires gravel, slightly more effort to clean
• Sponge filter: Suitable for fry tanks or supplementary filtration

Setup Procedure

1. Place the tank, add substrate and rinse
2. Fill with dechlorinated water
3. Install filter and heater (if needed) and start running
4. Run equipment empty for 1–2 weeks to allow bacterial colonization
5. Check pH and ammonia levels, then introduce goldfish

Layout and Considerations

• Substrate: Oiso gravel or field sand are easy to work with. Sand that is too fine can be accidentally ingested
• Plants: Goldfish eat most plants, so hardy species like Anubias and Java Moss are suitable
• Hiding spots: Not essential but helpful for stress reduction in crowded tanks
• Sharp objects: Avoid these as they can damage delicate fins

Find Goldfish on Bri-Choku

Once your setup is ready, it's time to find your favorite goldfish. On Bri-Choku's goldfish category, you can purchase healthy specimens directly from breeders. You can also get advice on variety selection suited to your environment.