The Penn Plax Tank Divider instantly turns 1 tank into 2 without major modifications to your tank. Perfect for separating rough and aggressive fish, the Divider won’t restrict circulation, filtration, or heating. Available in 4 different sizes to fit most tanks up to 55 gallons in size, the Divider is a convenient and efficient way to separate fish and fry. The perforated polymer screen allows continuous water flow and can be trimmed if necessary.