It is not hard to understand why plants are present in so many aquariums. Lush and healthy plants are stunning to look at and will create a much more natural environment in the aquarium. Most fish species feel safer and less stressed when they have plants to hide among, and many species will never thrive in an unplanted aquarium. If your fish species inhabit densely grown waters in the wild, they will feel very insecure in a plant without any vegetation. A lot of fish species are however rock dwellers and can get the same sense of security from caves and rocky formations in the aquarium. If your fish disturb the plants and damage them by nibbling of the leaves or digging up the roots, caves and wood can be a better solution than plants. If uprooting is the main problem, you can choose plants that float and do not require any anchorage in the substrate. If your fish are vigorous plant eaters, artificial plants can be used instead of live plants. It can also be possible to find a few live plant species that your fish do not like the taste of. If your fish only nibble on the plants, you can choose strong and fast growing live plants that can tolerate some snacking.
Plants will not only provide your fish with valuable shelters and make your aquarium look beautiful; they will also help you to keep the water quality up. Fish and plants coexist in the wild and will complement each other well in the aquarium. The waste products released by fish will contain compounds that the plants can use as nutrition. Organic waste will therefore be contained within the plant instead of floating around in the water where it can harm the fish. You should however keep in mind that these compounds will not "disappear", they will just be confined within the plant. If you allow dead and decaying plant material to stay in the aquarium, the organic compounds will be released again and begin to pollute the water. Plants must therefore be regularly pruned and unhealthy parts must be removed from the water as soon as possible. In return for the organic compounds that they receive from the fish, the plants will produce oxygen which is essential to the fish. The plants will also use dissolved carbon dioxide and thereby lower the levels of carbon dioxide in the aquarium.
The direct exchange between fish and plants is important, but it is not the only thing that help keeping the water quality up. The plants will also provide a home for a wide range of micro organisms that are beneficial for the ecosystem in the aquarium. Plants are also capable of inhibiting ugly algae growth since plants and algae compete over the same nutrients.
Many fish species will never spawn in an unplanted aquarium. Some species need the plants to feel safe enough to spawn, while others need leaves to attach their eggs on. A densely planted aquarium will also increase the fry survival growth if you wish to raise fry in the same aquarium as adult fish, since the fry will hide among the plants. Busy plants with a lot of smaller leaves are ideal for this purpose. It should however be noted that there are other ways to provide fry with good shelters. Newly hatched fry can for instance hide among larger marbles on the bottom of the aquarium. Caves, roots, stones and artificial aquarium decoration will also give the fry hiding places where they can stay out of harms way.
A plant relies on photosynthesis and light is therefore essential to it. A fish only aquarium requires little light, but if you wish to keep a densely planted aquarium you might be forced to install new lights. Fluorescent light is better than the standard incandescent light in planted aquarium. Some plant species are very demanding in require even stronger light than the fluorescent, but these species are not recommended for beginners. Fluorescent lights are more expensive than incandescent lights, but fluorescent lights will on the other hand burn cooler and use less electricity. Java Fern and Java Moss are two examples of suitable beginner species. They are tough plants that can survive in a wide range of pH-values and water hardiness. They can even be kept in a slightly brackish aquarium, such as a Molly aquarium.
Unlike many other aquatic plants, Java Fern should not be planted in the substrate in the aquarium. Java Fern should instead be attached to rock, wood or aquarium decorations where it will form roots. Once your have purchased your first Java Fern or Java Moss, the plants will propagate themselves. New plants will develop on the old plants, and eventually break off. You can attach these tiny plants to some type of decoration in the aquarium and wait for them to grow large.