Aquarium Starter Kit: What You Actually Need

The essentials

1. A filter rated for your tank size (don't undersize this)
2. A heater, if you're keeping tropical fish
3. A basic water test kit
4. Gravel or sand substrate

What can wait

• Fancy lighting — a basic light is fine to start
• CO2 systems — only needed for planted tanks

Cycle the tank for at least a week before adding fish. This is the step most beginners skip, and the one that causes the most problems.