Choosing Your First Fish

Most fish in a store are babies. They look small and cute in the tank, but many of them keep growing for years. Picking fish by how big they are in the store is one of the most common beginner mistakes.

Some popular fish that outgrow home tanks:

• Common pleco: often 15 to 18 inches or more
• Bala shark: about 12 to 14 inches, and it swims in groups
• Oscar: about 12 inches and very heavy-bodied
• Iridescent shark: can pass 3 feet long

None of these belong in a 20 or 30 gallon tank, even if they fit today.

The fix is easy: before you buy any fish, look up its adult size and minimum tank size. Every fish in our Species Library lists both. If the adult fish won't fit your tank, pick a different fish.

A good habit: take a photo of the fish's name at the store, then look it up before you pay. A few minutes of research saves a fish from a cramped life.