Your First Aquarium: a beginner's guide for Alberta

Short answer: for your first aquarium, buy a tank around 20 US gallons if space and budget allow, set it up with a filter, a heater, a thermometer, a dechlorinator and a test kit, and run it empty for a few weeks to grow the bacteria that keep fish safe. A bigger tank is steadier and more forgiving than a tiny one, so a 20 gallon is usually easier for a beginner than a 5 gallon. Add hardy fish last, a few at a time, once the water has settled.

Here is the whole process, in the order it actually happens.

Choose the tank first, and lean bigger

The most common beginner mistake is starting too small. A larger volume of water dilutes waste and holds a steadier temperature, so mistakes hurt less. For a first freshwater community, a 20 gallon is a comfortable size. A 10 gallon can work for a single betta or a small nano setup, and a 29 or 40 gallon gives you more room to grow.

Decide where it will live before you buy. A full aquarium is heavy — water alone weighs about 8.3 lb per US gallon — so it needs a stand rated for the load and a level, solid floor. Keep it out of direct sun and away from cold drafts, which matters in an Alberta winter. Browse tank options in our aquariums collection.

The beginner shopping list

• Tank and stand sized for your space.
• Filter rated for your tank size or the next size up.
• Heater for tropical fish, sized to the tank.
• Thermometer to check the heater is doing its job.
• Water conditioner (dechlorinator) for every drop of tap water.
• A liquid test kit for ammonia, nitrite, nitrate and pH.
• Substrate (gravel or sand) and a few plants or decorations.
• A light, and a lid or hood.
• A dedicated bucket and a gravel siphon for water changes.

For the filter, most beginners are well served by a hang-on-back model such as the AquaClear Power Filter, and our guide to choosing a filter explains the trade-offs. Match the heater to the tank using our heater sizing guide; a reliable adjustable heater such as the Fluval T-Series covers most community tanks.

Why the conditioner and test kit are not optional

Municipal tap water is treated to be safe to drink, and that treatment — chlorine or chloramine — is harmful to fish and to the beneficial bacteria in your filter. A conditioner neutralises it instantly. Seachem Prime is a concentrated option that handles both chlorine and chloramine, or you can browse the full water conditioners collection. A liquid test kit lets you see the water the way your fish experience it, which matters most in the first weeks.

Set it up, then wait

Rinse your substrate, fill the tank, add conditioner, and start the filter and heater running. Then comes the hardest part for a beginner: waiting. Before any fish go in, the tank needs to grow a colony of bacteria that turn toxic fish waste into something far safer. This is called cycling, and skipping it is the single biggest cause of early fish deaths. Our full walkthrough is here: how to cycle a new aquarium.

Local notes for Southern Alberta

Tap water here is generally hard, with a higher pH. That is good news for many beginner-friendly fish, especially livebearers such as guppies and platies, which prefer harder water. It also means you rarely need to chase pH — stable water suits fish better than water you are constantly adjusting.

Because winters are cold, keep the tank away from exterior doors and windows, and choose a heater at the higher end of its size range if the room runs cool.

Adding fish: last, and slowly

Once your test kit shows the tank has cycled, add a small first group of hardy fish, then wait a couple of weeks before adding more. Buy fish for the adult they become, not the small juvenile in the shop. To plan a combination that fits your tank, read how many fish can I keep.

Written by the team at Tropical Fish Imports in Lethbridge, Alberta. Last reviewed August 2026.

Setting up your first tank and not sure what fits your space or budget? Send us a message or visit the shop in Lethbridge — we are glad to walk through it with you before you spend a dollar.