Finfernhonest freshwater care · finfern.comNew Aquarium Checklist
The one idea behind all of it: fishkeeping is water-keeping. Get the water right — cycled, clean, stable, the right temperature — and most beginner problems simply never happen.
1 · Before you buy any fish
- Test (or look up) your tap water’s hardness — GH and KH. It decides which fish will actually thrive for you.
- Choose fish that suit your water and tank size — not just the ones that look nice in the shop.
- Check the adult size and group needs of every fish (many need a group of 6+, and the shop fish is a baby).
- Plan the whole stocklist first, so it fits one tank — don’t buy fish one impulse at a time.
- Pick the biggest tank you have room and budget for — a larger volume is more stable and more forgiving.
2 · Get the kit (function, not brand)
- A tank sized to your planned adult fish.
- A filter rated for your tank size or a little above (gentle flow for bettas and shrimp).
- A thermostatic heater — if your fish are tropical (goldfish and white clouds don’t need one).
- A thermometer, to confirm the heater is actually holding temperature.
- A liquid test kit (ammonia, nitrite, nitrate, pH) — more accurate and better value than strips.
- Dechlorinator (water conditioner) — treats every drop of tap water that goes in.
- Smooth sand or rounded gravel, plus some plants and hiding spots for cover.
3 · Cycle the tank FIRST (the step nobody mentions)
- Set up and fill the tank, treat the water with dechlorinator, and run the filter and heater.
- Start a fishless cycle — add an ammonia source and let the beneficial bacteria grow (about 2–6 weeks).
- Seed it faster with mature filter media from an established tank, or a quality bottled-bacteria starter.
- Test regularly. The tank is cycled when it turns a dose of ammonia into 0 ammonia and 0 nitrite within 24 hours.
- Be patient — patience is the cheapest equipment you’ll ever buy.
4 · Adding your fish
- Add fish gradually, a few at a time — each addition needs the bacteria to catch up.
- Float and slowly mix tank water into the bag to acclimate them to temperature and chemistry.
- Quarantine new fish in a separate tank for a couple of weeks if you can — it prevents most disease outbreaks.
- Add the most delicate fish (e.g. otocinclus, neon tetras) only once the tank is mature and settled.
5 · Your first 30 days
- Test the water every few days while it settles — clear water can still be unsafe.
- Do a small partial water change (roughly a quarter) each week, with dechlorinated, temperature-matched water.
- Feed lightly — only what’s eaten in a minute or two, once or twice a day. Uneaten food fouls the water.
- Learn your fish’s normal behaviour, so you spot a real change early.
- Don’t panic over early cloudiness or a little algae — both are normal in a young tank.