Is this too much for a 5 gallon aquarium

One Inch Per Gallon Rule

The most widely known rule for stocking a tank is one inch of fish per gallon of water. While this type of calculation works as a rough estimate, it leaves plenty of room for error. Like people, fish are not all the same size and shape. Stocking a ten-gallon tank with ten inches of slender shaped zebras is not the same as stocking it with ten inches of full-bodied goldfish.

Larger bodied fish create far more waste, and therefore require more water volume.

Furthermore, the fish often are not fully grown when first brought home. The adorable little catfish that is scarcely an inch long today could reach a half foot in size when it grows up. The true adult size of the fish must be used in the calculation. However, many owners have no idea how old their fish is or how large it will grow to be. Before making a decision, always research the fish in question to determine the true adult size.

Another place for error is assuming the size of the tank is equivalent to the number of gallons of water it holds. A ten-gallon tank filled with gravel, rocks, plants, and an assortment of decorations does not hold ten gallons of water. In reality the water volume is often ten to fifteen percent less than the size of the tank.

So while the one-inch per gallon rule is a reasonable yardstick, it has it's flaws.

Surface Area Calculation

The larger the surface area of the water, the greater the oxygen exchange, which in turns supports a larger number of fish. Therefore, surface area of the water directly impacts how many fish can be kept in an aquarium. A tank that is tall and thin may hold the same number of gallons as a tank that is short and wide, yet they have vastly different surface areas.