The classic rectangular aquarium shows off fish best because flat panes don`t distort. Beginners choose the Uniquarium Rectangle Aquarium because it comes with everything they need: high-capacity Bio-Fil filter silent submersible high-capacity pump a nd more. Pros choose it because they know that`s impressive gear maintaining perfect balance with no tubes pumps or hoses. Choose the size and tint to suit your individual taste. Sizes range from 20 to 300 gallons