Laterite Clays

What Is Aquarium Laterite?

Laterite creates improved growing conditions for rooted aquatic plants kept in aquarium gravel. It is a type of ancient clay  found on geographically old continents. Younger clays may also be useful, but the aging undergone by laterite removes excess phosphate that can cause undesirable algal blooms in your fish tank.

The commercial laterite available in pet stores is relatively unprocessed. The raw clay is extruded into pellets of a useful size for aquarium purposes.

How Laterite Helps Aquatic Plants

The benefits of laterite are all about more nutrients getting to the plants. If you are currently growing aquatic plants in gravel alone you may be less than pleased with the results. If you want to have success with more exotic plants while seeing robust growth in common rooted species then laterite is an excellent substrate improver.

1. This negatively charged mineral will actively attract plant nutrients. This delivers the nutrients where needed in a form that the plant can absorb.

2. It has a huge surface area compared with plain gravel. Laterite gives the plant root hairs more space for nutrient uptake.

3. The laterite itself can contain nutrients such as iron that your plant roots will feed on.

Preparing Aquarium Substrate Using Laterite

There is more than one way to use laterite in the aquarium. You can sprinkle it about in the gravel or bury balls in the laid substrate. The following is the procedure I usually follow when creating a new planted aquarium with laterite.

1. Mix laterite with moist aquarium gravel then allow it to dry. Use about a third of your total gravel for this.

2. Place clean layer of gravel on the aquarium bottom. Use a third or less of your total gravel.

3. Place a layer of laterite coated gravel on top.

4. Cover with a layer of clean gravel for two or more cm. Five cm is the most you will want to ensure adequate water flow.

5. To avoid disturbing gravel, place a saucer on top of gravel and fill the aquarium by pouring water onto this saucer.

6. Add plants to the aquarium gravel. Some pink colour may tint water but this will soon clear with filtration.

Using this procedure 250 grams treats about 1 square foot (30x30cm) of aquarium substrate area. Increasing or decreasing the amount may better suit the size of your gravel and the aquatic plants being grown. You can use laterite just in the places where you will plant or prepare the entire aquarium floor.

Laterite Disadvantages

Laterite is not for use with under gravel filters or with fish that dig up and move around the gravel. You really do need an undisturbed substrate to avoid water visibility problems.

Comercial laterite can be expensive. If you are lucky enough to live in places such as Australia you can probably find your own with a little geographi research and a digging implement.

Remember that the useful nutrients present in new laterite will be depleted with plant growth. Growth may become less vigorous with time unless the nutrients are replaced with an aquatic fertiliser.



The growth of the banana lily in the photograph was in an indoor aquarium using laterite and gravel. The pot it is in is only 5cm wide!

Plant Nutrients    Aquarium Plants