Get To Know More About Mangrove For the Reef Aquariums

Studies have shown the significant roles of algae and plants in the eco-system of all lakes, rivers, oceans or aquariums.

Many aquarist use plants and macro algae in reef aquarium to rise oxygen level and act as a natural filter and reduce algae growth. Mangrove is one of the few true plant that can survive in saltwater. There is somewhere close to 50 species of mangrove spread wordwide. In the wild, mangroves branches provides shelter for many birds while roots provide hiding place for organisms such as fish and various invertebrates.

They became popular in the aquarium hobby not only for their ability to remove phosphates and nitrates but also to create interesting display.

They are slow-growing plant so their nutrient uptake is limited. Because of that, they will certainly not remove as many phosphates and nitrate as some other plants or algae. If you are trying to solve a high pollution problem caused by overfeeding, insufficient filtration or overstocking your tank, mangroves might not be enough. Mangroves will help but won't do all the work. The concept of natural filtration (no filter) by using mangroves and macro algae became popular but we have to remember that natural filtration system also involve live sand, live rock and a well balanced fish population.

How many will I need? It's impossible to tell how many mangrove will be needed to make a difference in your tank. This depend on how much phosphates and nitrates you want to remove and also the size of the mangrove. A large mangrove will certainly do a better job than a small one. Let's start with about 2 mangrove per 10 gallons and adjust if needed.

Where to grow mangrove? In the main tank: A good way to use the mangroves is to plant them directly in the main tank to mimic some interesting biotopes like fringing reef that surrounds an island. Mangroves will provide habitat for the fish. Some snails like the Cerith Snail and the Dwarf Planaxis Snail love to burrow around mangrove's root system. This won't work with a light hood; tanks need to be open on the top so the plants have space to grow.

In a sump: If you feel your tank is not suitable for mangrove in the main tank, it is possible to simply grow them in a sump. To do this, the sump will have to be equipped with a lightning system and a suitable substrate.

Mangrove island: I have seen some people using mangrove to create floating island by planting them in styrofoam. To do this, simply poke holes in a styrofoam block and push mangroves in the holes. Since mangrove will grow and soon reach the light, this may not be a viable alternative.

Choosing your mangrove:

Mangrove can be bought as propagules (a sprouting young plant) or as seeds. Propagules are generally hardier, but are often unsuitable for small tanks because of their size and shape. However, they are usually a good choice for larger tanks. The seeds grow into a plant that will adjust its growth to the light and the aquarium which give them a more natural tree-shape. Unfortunately, are often more sensitive to the heat produced by strong light like metal halide. If available, try to get Rhizophora mangle because its is very hardy. The down side of this species is that leaves will need to be washed on a regular basis (see bellow). If buying a propagule, try to chose some that have good roots and healthy green leaves.

What does mangrove need to grow?Ideally, seeds will be planted in a substrate made of sand or mud and can also be planted in between rocks (yes they can root in lime rock!). For good growth, substrate should be 1.5 to 3 inches deep. Mangrove are not picky when in comes to lighting. Any compact luminescent lamps of about 40W will do the job. Don't place light too close to the plants because the heat may kill the leaves. Also, make sure the plants don't shade corals by growing directly under the lamps. Remember that 12 to 18 inches (or more with MH light) between the plants and the light is a good rule. The best light for mangroves and any other plant is a daylight lamp at 6,000 Kelvin. Light should run 10 to 12 hours a day.

Where ever where you plant it, remember that the tip of the plant must be above water surface. For best results, room temperature should be at least 70 degrees.

Now, what's next?

As said above, mangroves will use available phosphates and nitrates to grow. Regular trimming will be needed to control the size of the plant. By trimming the plant, not only you control it's size but you also remove nitrates and phosphate that was stocked in it. Death leaves should also be removed otherwise nitrates and phosphates stocked in the leaves will simply go back into the water.

Some species like Rhizophora mangle exports salt by producing a thin layer of salt crystals on top of their leaves. This should be washed at least three times per week - by spraying fresh water on the mangrove. Some other species deposit excess salt inside of their oldest leaves, which then will turn yellow and drop down. This is a natural process and all we can do is to remove the death leaves before they dissolve in the water.