Everything you need to start a fish tank

Here's exactly what to buy for a first freshwater tropical tank, what you can skip, and the mistakes that cost beginners the most money.

Start with a 20 gallon tank if you can

It sounds backwards, but bigger tanks are easier. More water means waste and temperature changes happen slowly, so small mistakes don't hurt your fish as fast. A 20 gallon tank is a good balance of easy care, fish choices and cost. Avoid bowls and tanks under 5 gallons.

Not sure how much your tank holds? Use the aquarium volume calculator.

Must-haves

• Tank and lid. A lid stops fish jumping out and slows evaporation.
• Stand. Water is heavy: a set-up 20 gallon tank weighs about 200 lb. Use a stand made for aquariums.
• Filter. Choose one rated for 4–6 times your tank's volume per hour. A hang-on-back or sponge filter is easiest for beginners.
• Heater. Most tropical fish need 75–80°F. Plan on 3–5 watts per gallon.
• Thermometer. Heaters can fail or drift, so check the temperature yourself.
• Water conditioner. Removes chlorine and chloramine from tap water. Use it every time you add water.
• Liquid test kit for ammonia, nitrite, nitrate and pH. You'll need it to cycle your tank.
• Gravel vacuum (siphon) and a bucket used only for the aquarium. Soap residue can kill fish.
• Substrate. Gravel or sand, about 1–2 inches deep.
• Light. A simple LED is fine, and you'll need a better one only if you grow lots of live plants.
• Fish food and a small net.

Nice to have

• Live plants such as java fern, anubias and Amazon swords. They're hardy, they help keep the water clean, and fish like hiding in them.
• Hiding spots like rocks, driftwood or caves.
• Bottled beneficial bacteria to help cycling along.
• An outlet timer so the light runs about 8 hours a day without you remembering.

What to skip

• "Starter kits" with tiny filters and heaters. Check the specs before buying one.
• Chemicals that promise to fix everything. Regular water changes do more.
• Buying fish on the same day as the tank. The tank needs to cycle first.

How much does it cost?

A basic 20 gallon setup with everything on the must-have list usually costs somewhere around $150–$300, depending on the stand and filter you choose. Fish and plants come on top of that. Watching for sales and buying a used tank (checked for leaks) can save a lot.

Your setup order

1. Put the stand where it will stay, away from windows and heat vents.
2. Rinse the substrate and decor in plain water, never soap.
3. Add substrate, decor and plants, then fill the tank with conditioned water.
4. Install the filter and heater and turn them on.
5. Cycle the tank for 4–8 weeks.
6. Add a few hardy beginner fish, then more over the following weeks.