These highly unusual plants are as beautiful as they are interesting. They are also highly functional, especially for marine or brackish aquariums. Thanks to their astounding evolutionary developments needed for survival in the wild, they have many elegant benefits for aquarists. During this blog piece, we’ll discuss what mangroves actually are, what the benefits of adding them to your tank are and how to grow them.

What Are Mangroves?

Mangroves are a highly specialised tree species, which have become highly adapted to their environment. These special plants are found throughout the tropics and subtropics along coastline and river edges. They have a unique ability to survive in very salt-rich, oxygen-poor soils as well as in hot environments. Mangrove forests are flooded twice a day with the wide in coastal habitats, so mangroves employ their filtration systems to grow and survive. Different species have different salt-tolerant survival techniques. Some species will filter out the salt within the water before absorbing it, whereas others will first take in the water and then secrete it through their leaves.

Mangroves gradually develop long and extensive root systems, reaching deep underwater that provide a sheltered nursery habitat for young fish that allow them to develop safely hidden from predators. Above the water level their dense canopy is utilized by birds, insects, monkeys and sloths. Mangroves engineer an entire environment and food chain from sponges, barnacles and oysters to many types of fish. Therefore, mangrove forests are vital for many species, including many endangered species, for the food and shelter they provide. 

Crucially, mangroves are also playing a vital part in offsetting climate change. Through a process known as carbon burial, they absorb and store large amounts of carbon dioxide. Mangroves also use carbon in their leaves and branches in order to grow. By removing this harmful atmospheric carbon, it helps reduce the amount of greenhouse gases in the atmosphere. Despite making up only 2% of aquatic habitats, they are responsible for approximately 10-15% of carbon burial globally. 

Why Have Mangroves in Your Aquarium

As you can see, mangroves have some interesting adaptations that aquarists can take advantage of. Keeping mangroves allows you to decorate a tank at the top, imitating a fringing reef environment instead of just having a simple tank lid. Their lush green leaves emerging from your saltwater tank aquarium are beautiful and intestersting. Secondly, you can use mangroves for nutrient control. The bigger they grow, the more effective they are at removing excess nutrients such as nitrates, phosphates and organic waste. Essentially, mangroves to keep your tank in balance through controlling nutrient levels, in a more elegant and beautiful way than using macroalgae.

Growing Mangroves in Your Aquarium

You’ll be glad to know that this isn’t a ‘sounds too good to be true’ scenario, mangroves are also easy to care for. We recommend you buying mangroves such as Rhizophora mangle as small shoots that are slightly more established. Rhizophora mangle is a great optio, it is very hardy and will adjust to your tank water parameters. We also would not recommend, as with corals, in taking mangrove propagules from the wild. Taking wild plants can damage their sensitive aquatic environments and is generally unsustainable, wild harvesting is also illegal in many localities. To preserve and protect these important environments, ensure your mangrove shoots are being sourced from sustainable suppliers. 

Mangroves can be planted in the sand, mud or in between rocks in any open-topped aquarium, with the branches and leaves coming out of the water. A very simple way to plant mangrove shoots is by pushing the shoot between two or three porous rocks, allowing their roots to grow into the pores. For a bigger impact, you can also use small baskets that hang over the edge of your tank and then fastening the shoots with nylon cable ties. The roots will quickly take hold in either a sand substrate or in a live rock. Your mangroves will then also begin to absorb nutrients from the water in order to grow. It is important to note that when the leaves fall off the plant, they should be cleaned up immediately. Occasionally, your mangroves will also appreciate being sprayed with freshwater to mimic rain washing off excess salt from their leaves. For Rhizophora mangle, this should be done at least two or three times per week,

In terms of lighting your mangroves, they need similar lighting requirements to a regular refugium. As mangroves photosynthesis, they prefer sunlight or at least full spectrum light. You will need to be strategic about your mangrove placement to avoid shading your corals. Mangroves should also be kept away from metal halides and excessive heat.

Fish and Invertebrates for Mangrove Aquariums

Just as with a purely coral reef tank, it is worthwhile creating a natural environment in your saltwater tank. We suggest adding fish that mimic fish that shelter in mangroves. Therefore, a shoal of cardinals such as pajama cardinalfish (Sphaeramia nematoptera) would look amazing. Bottom-dwelling species would also work well in shallower tanks such as jawfish like the blue dot jawfish (Opistognathus rosenblatti). Various species of goby or blenny would also work well. Our recommendations are the Hi Fin Red Banded Goby (Stonogobiops nematodes), Yellow Watchman Goby (Cryptocentrus cinctus), Neon Goby (Elacatinus oceanops), Randall’s Goby (Amblyeleotris randalli) and Yasha Hase Shrimp Goby (Stonogobiops yashia). In terms of blennies, we love the midas blenny (Ecsenius midas), and the scooter blenny (Synchiropus ocellatus).

Invertebrates are also great additions, as they will make the most of the interesting root system.  Aquarists could choose a number of filter feeders, such as sponges, and crustaceans, like the porcelain crab (Porcellana sayana). This could also include a whole host of shrimp species, including the sexy shrimp (Thor amboinensis) and the peppermint shrimp (Lysmata wurdemanni).

Mangrove Care Summary:

Minimum Tank Size: 20 Gallons

Diet: Nitrates

Care Level:  Moderate

Lighting: Medium

Reef Safe:  Yes

Temperature: 72-78° F 

dKH: 8-12

pH: 8.1-8.4

We challenge you to step outside of the norm and try adding mangroves to your reef aquarium for nutrient control. We love these gorgeous plants in any suitably sized reef tank.