What size tank is good for a starfish?

A starfish typically requires a tank of at least 20 gallons to thrive, as they need ample space to move and explore. It's important to ensure the tank has stable water conditions, as starfish are sensitive to changes in salinity and temperature. Additionally, a well-maintained tank with plenty of hiding spots and live rock is beneficial for their health. Always research the specific species of starfish you plan to keep, as their needs can vary.