Betta Fish
A colourful fish that needs warm, clean water and an appropriately sized tank.
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Explore aquarium fish and learn about tank cycling, water quality, compatible species, feeding and maintenance for a stable aquatic environment.
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Fish Information
Explore aquarium fish and learn about tank cycling, water quality, compatible species, feeding and maintenance for a stable aquatic environment.
- Physical characteristics and typical size
- Temperament, social needs and activity level
- Feeding, grooming and suitable housing
- Preventive care and common health considerations
Choosing the Right Companion
Consider your routine, available space, budget, experience and the time you can offer for care. For freshwater aquarium fish, research tank volume, water chemistry, filtration and species compatibility before choosing.
Read Pet Care Guides →Pet care across the United States and Canada
Climate, housing and veterinary access vary by state, province and municipality. For freshwater aquarium fish, check seasonal risks and identify a qualified professional with relevant species experience.
Frequently Asked Questions
How do I choose the right fish?
Compare tank volume, water chemistry, filtration and species compatibility, temperament, adult requirements and expected lifespan with your household routine. Ask a qualified professional about any needs you are unsure how to meet.
What should I prepare before bringing a fish home?
Before bringing home freshwater aquarium fish, prepare the right habitat, suitable food, clean water and enrichment, and identify a qualified veterinarian.
Where can I learn about individual fish?
Open a profile card for a focused freshwater aquarium fish guide with individual facts, daily care details, nutrition notes, health considerations and common questions.
Aquarium Fish Species and Freshwater Tank Care
Use this freshwater aquarium fish directory as a starting point for responsible ownership. Confirm individual care plans with qualified professionals.
Plan the aquarium before buying fish
Choose an aquarium based on the adult size, swimming behaviour, social needs and water requirements of the species you intend to keep. A small container is not a suitable default home for every fish. Research whether the fish is territorial, schooling, a fin-nipper, a bottom-dweller or a fast swimmer. Guppies, mollies, bettas, goldfish, neon tetras and angelfish have different care requirements and may not be compatible in one tank. Consider the weight of a filled aquarium, a stable stand, electrical safety and access for maintenance before setting it up.
Understand cycling and water chemistry
A healthy aquarium depends on biological filtration. Before adding fish, learn how the nitrogen cycle works and how beneficial bacteria process toxic ammonia and nitrite. Test water rather than judging it by appearance: clear water can still contain harmful compounds. Monitor temperature, pH, ammonia, nitrite and nitrate using appropriate tests. Tap water may require a suitable dechlorinator, and source-water chemistry can vary between cities and local water supplies and local supplies. Make gradual adjustments and avoid sudden changes that can stress fish. Never add a large number of fish to a new aquarium all at once.
Feeding, filtration and maintenance
Feed a species-appropriate complete diet in small portions that fish can consume without leaving excess waste. Overfeeding is a common cause of poor water quality. Maintain filtration and water movement suitable for the species, and clean filter media in a way that preserves beneficial bacteria. Regular partial water changes help manage dissolved waste; the schedule depends on stocking, filtration, feeding and test results. Avoid washing filter media with untreated chlorinated tap water. Keep a maintenance log so trends can be noticed before they become emergencies.
Compatibility and fish health
Do not mix fish solely because they look attractive together. Compare adult size, temperature range, water chemistry, temperament and social behaviour. Quarantine new fish when possible and observe them before introducing them to an established aquarium. Watch for clamped fins, unusual swimming, rapid breathing, loss of appetite, spots or isolation. These signs can have several causes, including water-quality problems, parasites or infection. Test water first and consult an aquatic veterinarian or experienced qualified professional rather than adding random treatments.
Frequently asked questions
A filter does not remove the need for water changes and testing. Goldfish commonly require more space and filtration than beginners expect. Bettas also need stable warm water and suitable filtration; a tiny unheated bowl is not an appropriate long-term habitat. The safest aquarium is planned around the needs of its inhabitants, not the number of fish a shop tank can temporarily hold.
Common questions about fish
Can I add fish immediately to a new aquarium?
Do not add fish until the aquarium is properly prepared and its biological filtration is established. Learn the nitrogen cycle and test ammonia and nitrite.
How do I know aquarium water is safe?
Use appropriate tests for ammonia, nitrite, nitrate, pH and temperature. Clear-looking water can still contain harmful compounds.