As a gardener I love playing with the aquarium plants, you can garden inside on a wet day! Plants for an aquarium are specifically for growing in water. Some are sold as aquarium plants but are really for growing by or near waterways, swamps or bogs. These do not live for long when there are completely submerged. Aquarium plants are a bit like exercising you do not notice any differences until it is not there. They are useful for assisting the water filtration, to enhance the water for the fishes. They have the ability to absorb nitrates. This along with producing oxygen and absorbing carbon dioxide they can be a valuable addition to the tank.
While I had under gravel filters, they were not my main choice for filtration. However, for the plants it was just fine, as much detritus from the fish settles at the bottom of the tank and finds its way beneath the filter. This provides nutrients for the plants. There are plant foods available especially for the aquarium plants. Personally, I never bothered, for their growth rates were huge and to feed them even more was ridiculous and money down the drain. I can understand it for special plants that do need additional food. Never ever use proprietary houseplant food as you may end up killing your fish!
Choosing fish for the tank with the plants in mind is also important, as some will pull plants out of the gravel, others will eat them. Guppies and their community mates are not in that league, although you will see them picking at the plants. I also had a lighting system above the tanks to encourage growth. Switching the light off at night to give both fish and plants the normalcy of a twenty-four hour day.
Aquarium plants are easily propagated, generally doing it by themselves. Vallisneria send out runners, or if you do not want them there cut the runner and plant it somewhere else or in a new tank. The floaters grow laterally and you will find the small green plants on top expanding. I did not have these as I felt the water to air transfer was hindered. For the guppies and their mates, Cabomba was ideal as the leaves are fine and the fry were very happy hiding out in them. It also grew at great rate. Do not dispose of your aquarium plants in your local streams or waterways, they have the ability to spoil and become a nuisance.
Chose your plants with care, keep the shorter or smaller ones in the front of the tank and the larger or longer ones at the rear. If you plant before adding the fish, they will have time to grow and you will be able to adjust “your picture”. Plants for your aquarium may include salvinia, cabomba ,the red and green varieties, Amazon sword plants, canadian pond weed(oxygen weed) there will be others ask your supplier what is right for you and your aquarium if you have any doubts.