Before your first freshwater fish
Prepare the aquarium before you bring its residents home.
General care guidance. Needs vary by species, age and health. Your veterinarian can tailor a plan for your pet.
Prepare the water first
Set up and cycle the aquarium before adding fish. A new filter needs time to develop the bacteria that handle fish waste.
Use a test kit to check ammonia, nitrite, nitrate and pH. Ask for a water-care plan for your chosen species.
Choose compatible fish
Match fish by adult size, water needs and social behavior. Add stock gradually; a small fish may need much more space as it grows.
Keep the aquarium stable and away from strong direct sunlight. Use species-specific advice for temperature and safe introduction.
Sources & further reading
Sources checked October 21, 2026. These are original starter summaries; read the full guidance below.