Dwarf lilies are the best bet when trying to grow lily pads in an aquarium. The leaves grow no more than 4.7 inches long, so you can fit more than one in each tank. They are reddish-pink in color, adding visual appeal. Lily bulbs are hardy and thrive in a cold water or freshwater tank with goldfish and other similar species. Fish make waste that the lily pad uses as food. They also help eliminate toxins in the water, keeping your tank cleaner.
Regulate the aquarium water so the temperature is between 72 and 82 degrees Fahrenheit. This is ideal for lily pads. They also need a pH of 5.5 to 7.5. Get a pH test kit from an aquarium supply store and test the pH. Make the necessary amendments based on the test results.
Place a dwarf lily bulb in the water. It will sprout with water alone, but you can also bury it under the substrate at the bottom of the tank to hold it in place. Expect it to take one to two weeks for the bulb to sprout.
Remove the sprouting bulb from the aquarium as a way of encouraging growth. Fill a plant pot halfway with soil. Put the bulb in the soil and fill the container the rest of the way up. This will keep it safe from snails or fish that eat plants and help it grow larger.
Set up a fluorescent light on top of the aquarium or on top of the plant pot to provide the bright intense light lily pads need. A full spectrum light is best and will make the lily pads grow faster. If the light is dim, the lilies will grow but won't develop the shoots that later become lily pads.
Leave the intense light on for 12 hours per day. This will encourage the lily bulbs to form pads. If the lilies are in a plant pot, place them back in the aquarium once they develop into lily pads.