First Fish Checklist: what to do before bringing your fish home

Quick answer

Before you buy fish, set up the tank with a filter and (usually) a heater, add water conditioner, and cycle the aquarium so the water can process waste safely. Get a liquid test kit and confirm ammonia and nitrite are zero before introducing fish. This one step prevents most "new tank" problems.

The essentials you should have

• Tank: bigger is easier to keep stable (20L to 60L is great for beginners)
• Filter: gentle flow, sized for your tank
• Heater: for most tropical fish (aim for a stable temperature)
• Water conditioner: removes chlorine/chloramine
• Liquid test kit: ammonia, nitrite, nitrate
• Thermometer
• Substrate and decor: gravel or sand, plus hiding spots
• Fish food: appropriate for the species
• Siphon and bucket: for water changes (dedicated to the tank)
• Optional but helpful: live plants, timer light, simple algae scraper

Step 1: set up your tank (before fish)

• Rinse substrate with water (no soap).
• Place substrate and decor.
• Fill the tank and add water conditioner.
• Install the filter and heater.
• Let everything run for 24 hours and confirm the temperature is stable.

Step 2: cycle the tank

Cycling builds beneficial bacteria that convert toxic waste into safer compounds.

• Add a source of ammonia (fish food, or pure ammonia made for cycling).
• Test the water every few days.
• Keep cycling until ammonia is 0 and nitrite is 0 after an ammonia dose, and you see nitrate.

Most tanks take 2 to 6 weeks to cycle.

Step 3: bring fish home safely

• Start with a small number of fish.
• Float the bag to match temperature.
• Slowly mix tank water into the bag over 15 to 30 minutes.
• Net the fish into the tank. Do not pour store water into your tank.

The first-week routine

• Feed lightly (small amounts once a day).
• Test water a few times in week one.
• Do a partial water change if ammonia or nitrite rises above zero.
• Keep lights on a simple schedule to reduce algae.

Common mistakes to avoid

• Adding fish before the tank is cycled
• Overfeeding
• Cleaning the filter media with tap water
• Replacing all filter media at once
• Doing 100% water changes

FAQ

Do I really need to cycle the tank?

Yes. Cycling prevents ammonia and nitrite spikes that stress or kill fish. It is the biggest difference between a smooth start and constant problems.

What is the easiest beginner fish setup?

A simple freshwater community tank with a filter, heater (if tropical), and a few hardy fish. Bigger tanks are more stable and easier for beginners.

How often should I change the water?

Most tanks do well with a weekly partial water change. The exact amount depends on stocking level, feeding, and test results.

Can I use a bowl for fish?

A bowl is hard to filter, heat, and keep stable. Most fish do better in a properly sized aquarium with filtration.

Next step

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