Plant Maintenance

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Aquatic plant being trimmed

A planted aquarium requires the same basic maintenance as any aquarium. Water changes, water testing, glass cleaning etc. all need to be done as normal. To keep plants looking 'fresh' and healthy, they will also need regular attention. Trimming old leaves, adding fertilisers, removing mulm as well as keeping lighting systems efficient will all help to keep a planted aquarium looking its best.


An efficient and effective planting substrate should actually contain a large amount of organic material, so it does not need cleaning as often as an aquarium without plants would. In most cases, regular removal of waste (organic matter) material using a gravel cleaner will reduce the chance of bacterial infections of fishes as well as reduce algae and improve water quality. In a planted aquarium, the organic waste within the substrate is needed to hold and supply nutrients to the roots of the plants. However, this is only needed in the lower half of the substrate. The top few centimetres should still be regularly cleaned and waste matter removed. This should be done with care, avoiding any damage to plants. A gravel cleaner works by siphoning water from the aquarium and lifting waste matter whilst dropping the substrate behind. Gravel cleaning should ideally be done every week, and can be done at the same time as a water change. The 'waste' water removed by gravel cleaning can be replaced by fresh, dechlorinated water.

Over time a fine grade substrate will compact and 'fill' with organic material, when this happens water movement may completely stop. The substrate then becomes stagnant and may produce gases that encourage algae and damage roots. To prevent this a simple 'finger test' can be carried out every few months. You should be able to push a finger to the base of the substrate with a little resistance. If it becomes very hard, then it should be gently disturbed across the entire base of the aquarium. This process need only be done every few months.

Trimming and cutting

Most plants will continually produce leaves or grow towards the surface, over time 'old' leaves will develop brown patches and begin to look a little 'worn' or tatty. When this starts to happen, the old leaves should be removed at the base of the plant. New leaves should then grow in place of the old ones. Stem plants that begin to get too large can be trimmed. Any trimmed sections should be at least 10cm long and taken from the top of the plant. The cuttings can be replanted in the substrate and should begin to grow as separate plants. The original plant will also continue to grow from the site of the cutting, and may also grow side-shoots, creating a bushier appearance. Continual trimming and removal of old or large leaves will, over time, cause the plant to grow more slowly and more compact. Eventually, a plant may stop growing and may need to be replaced; this can be done as and when needed.

Separating plants

Plants that produce leaves from the base (without a visible stem) will continue to spread outwards and become continually larger. Most plants of this type actually produce separate 'daughter plants' at the base. Once the plant becomes significantly larger than its original state, it can be taken out of the substrate and the daughter plants removed and re-planted as separate individual plants. A similar process can be done with plants that grow from a central horizontal root or rhizome such as many plants which root on rocks or wood. These plants spread horizontally with individual shoots produced along the rhizome. A plant that contains a number of shoots can be cut across the central root, with several shoots in each section and replanted as separate plants.


Spot lamps such as metal halide or mercury vapour lamps do not lose intensity and can be simply replaced in the same way a household bulb is when it blows. Fluorescent tubes however, will lose a large percentage of their intensity over periods of time. This loss of intensity may not be obvious to the fish keeper but will have an effect on the aquariums plants. To keep lighting intensity at a sufficient level it is wise to replace fluorescent tubes every 12 months, even if they appear to be working normally.

Lighting intensity can also be kept high by regular wiping of the tube and any cover glass or condensation tray(s) in the aquarium.

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