Step 1: Choose tank size and location

Pick a spot away from direct sunlight and drafts. Bigger is easier: 20–30 gallons is a sweet spot for beginners. See our first tank guide for why. Have a stand that can hold the weight (water is heavy). If you are choosing tools to track setup and maintenance, compare options on our aquarium app page.

Step 2: Rinse substrate and add decor

Rinse gravel or sand until the water runs clear. Add a few inches to the bottom. Place decor and (if you want) plants. Leave space for the filter and heater.

Step 3: Add water and install equipment

Fill with dechlorinated water. Install the filter and heater; run both. No fish yet. Let the tank settle and the heater reach temperature (typically 76–78 °F for tropical).

Step 4: Cycle the tank

This is the step most beginners skip — and the one that saves fish. Read our how to cycle a fish tank guide. Use fishless cycling: add an ammonia source, test until ammonia and nitrite hit zero. Usually 2–6 weeks. Track your tests in App-aquatic so you see progress.

Step 5: Add fish slowly

When the cycle is done, add a few fish first. Don’t stock the whole tank in one go. Test for the next few weeks and do water changes as needed. Plan who goes in with our best fish for 10 gallon or overstocking guides.

Quick takeaways

Location → substrate → water → filter & heater → cycle → fish. In that order.
Never skip cycling. Fishless is safest.
Add fish gradually and keep testing. Plan your stock before you buy.

How to set up a fish tank