Freshwater aquarium guides, organized.
Everything we have written for fishkeepers, sorted by what you are trying to do.
In-depth guides
Long-form references we keep up to date.
Freshwater Aquarium Water Parameters
What ammonia, nitrite, nitrate, pH, GH, KH, and temperature numbers mean, and what to do when they are off.
Read the guide →GuideThe Planted Aquarium Fertilizer Guide
What plants need, root tabs vs liquid fertilizer, reading deficiency symptoms, and starter routines for any tank.
Read the guide →Getting started
Setting up a first tank and avoiding the mistakes almost everyone makes.
- Beginners Guide to Setting Up a Freshwater Aquarium
- Aquarium Nitrogen Cycle: Why Your Fish Keep Dying (And How to Fix It)
- Choosing the Perfect Fish Tank Size
- Modern Fish Tank & Aquarium Kits: What to Look For
- 5 Common Freshwater Aquarium Mistakes and How to Avoid Them
- How to Set Up a Quarantine Tank for Fish (And Why It Might Save Everything)
Water and equipment
Water changes, filtration, and lighting without the guesswork.
- How Often Should You Do a Water Change? (And How to Do It Right)
- Why Water Changes are Essential for a Happy and Healthy Aquarium
- Filter Frenzy: How to Choose the Best Filter for Your Freshwater Aquarium
- The Importance of Aquarium Lighting Explained
- How to Clear Green Water in an Aquarium With Sera Siporax
Plants and hardscape
Live plants, wood, and rock for planted tanks.
Fish care and species profiles
Care guides for the fish we get asked about most.
- Cardinal Tetra Care Guide: Everything You Need to Know
- Species Profile: Neon Tetra (Paracheirodon innesi)
- Rummynose Tetra: The Little Fish With the Big Warning Light
- Corydoras Catfish for Community Tanks: Why Every Freshwater Setup Needs Them
- Otocinclus Care Guide: Why Oto Catfish Keep Dying and How to Fix That
- Celestial Pearl Danio Care and Breeding Guide
- How to Care for a Betta Fish in a Small Aquarium
- Species Profile: Pea Puffer - Everything You Need to Know
- Species Profile: Ram Cichlids (Mikrogeophagus ramirezi)
- Species Profile: Yellow Lab Cichlid (Labidochromis caeruleus)
- Species Profile: Golden Mbuna (Melanochromis auratus)
- Meet the Blood Red Parrot Cichlid: A Colorful and Easy-to-Care-for Fish
Choosing fish for your tank
What to buy, how many, and who gets along.
Shrimp and invertebrates
Cleanup crews and colorful shrimp.
Feeding
Making food that fish actually eat.
Local services and families
Maintenance help, store guides, and aquariums for kids.
More guides
Everything else in our library.
Want it in person?
Bring your tank questions to the store. We would rather help you get it right the first time.