Fish

Every betta in a store cup is a tail shape plus a color pattern. Here is how to name all of them, and which types are hardest to keep alive.

Koi live 25 to 35 years in a proper pond and 5 to 15 in a tank. What drives the difference, plus the truth about the 226 year old koi.

The common goldfish grows to 14 in and can live 25 years. Tank size for one or two fish, safe tank mates, and the mistakes that kill most pet goldfish early.

Cichlids are colorful, territorial and easy to feed, but the group you pick decides the water, the tank size and the tank mates. Here is how the six main types compare.

Every freshwater angelfish belongs to one of three Pterophyllum species. Sizes, group numbers, water, price and the tank mates that fail.

Goldfish hold trained associations for at least three months and recognize the people who feed them. Here is what the research actually shows.

A koi pond needs 3 ft of depth, 1,000 gallons, and hourly filter turnover. Here is what that costs, how to keep the water clear, and what really preys on koi.

Wild bettas are small, brown, short finned, and nothing like the fish in the cup. What they cost, how big they get, and whether they really live in puddles.

What one koi fish actually costs, why show grade fish reach thousands, how much pond water each adult needs, and what takes koi from a backyard pond.

Tetra fish need a school of six or more to behave normally. Here is what they cost, which species suit beginners, and why some batches die in week one.