7 Best Marine Plants for Reef Tanks

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Saltwater plants receive less attention than their freshwater counterparts. Still, you can add many beautiful species to your reef tank. The trick is to choose the ones that can withstand the salinity, pH, and hardness level needed for corals.

Not sure where to start? Keep reading! This article covers seven of the best marine plants for reef aquaria. Below you’ll find some of the most interesting-looking choices to transform your aquarium display. Here they are, in no particular order!

Sea Lettuce (Ulva Lactuca)

  • Care Level: Easy
  • Growth Rate: Fast
  • Lighting: High
  • Water Parameters: 72-78°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.026 SG
  • Supplementation: CO2, Iron, Magnesium, Trace minerals

Sea Lettuce is among the most popular marine plants. It’s affordable, easy to find, and very easy to grow. As long as it gets enough nutrition, this species can grow up to 7 inches in length and 12 inches across.

Sea Lettuce grows thin, broad oval leaves with ruffled edges. Its bright green color stands out against pale sandy and coral substrates. Like other macroalgae species, Sea Lettuce is very good at removing phosphate and nitrates in the water column, so it’s a good addition to reef tanks.

This plant is a good supplemental food, and herbivorous fish usually love feasting on it. Sea Lettuce could also provide cover for fish while breeding or nesting if it doesn’t get eaten too fast.

Caulerpa Prolifera

  • Care Level: Easy
  • Growth Rate: Fast
  • Lighting: Moderate
  • Water Parameters: 76-84°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.026 SG
  • Supplementation: CO2, Iron, Magnesium, Trace minerals

Caulerpa Prolifera is a very hardy and beginner-friendly plant. It can adapt to a variety of water parameters, including high temperatures. It has moderate CO2 and light requirements but still grows very rapidly. This algae species is very efficient at filtering phosphates, ammonia, and nitrates from the water column, making the aquarium stable and safe for corals.

Caulerpa Prolifera grows up to 6 inches high and has oblong curly leaves. Its considerable size makes it a good hiding place for small and medium-sized fish. Unsurprisingly, its many benefits make this plant a popular addition to reef tanks. The high demand makes this macroalgae species easy to find in most stores.

Green Finger (Codium sp.)

  • Care Level: Easy
  • Growth Rate: Slow
  • Lighting: Moderate
  • Water Parameters: 72-82°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.026 SG
  • Supplementation: CO2, Iron, Magnesium, Trace minerals

One of the perks of marine tanks is keeping the weird, alien-looking plants you never see in freshwater environments. The Green Finger is one such species. The name is self-explanatory. Codium Spongiosum is a green macroalgae species with branched and stubby finger-like growths.

The branch-like algae filaments are tough and calcareous. This is great because most fish won’t flock to eat this plant due to its unappealing texture. Its slow growth means you need less supplementation and won’t need to prune the plant often.

Green Finger algae are also foolproof because they don’t need planting. You don’t need any special substrate but can anchor this bushy plant to rocks and other ornaments. Under the right conditions, the Green Finger can grow up to 1’3’’, making it an excellent addition to large aquariums.

Like most algae, this species is reef-safe and provides good water filtration. It’s not the best hideout for fish, but its unique appearance sure adds something extra to your aquarium display!

Shaving Brush Algae (Penicillus)

  • Care Level: Easy
  • Growth Rate: Fast
  • Lighting: High
  • Water Parameters: 72-78°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.025 SG
  • Supplementation: CO2, Iron, Calcium, Trace minerals

Would you like an aquarium plant that looks like a little tree? Well, it’s your lucky day because the Shaving Brush is exactly that. This green plant grows a high, sturdy stalk that spreads out into multiple thin filaments. The top bushy growth resembles a lush tree crown or a shaving brush.

Shaving Brush algae grow fast and reach a maximum height of 1 foot. It looks great in tall aquariums and as a background plant. Its rapid growth comes with high CO2, light, and mineral requirements, though. On the flip side, the Shaving Brush filters phosphates and nitrates, keeping your corals healthy.

The Shaving Brush takes a lot of calcium to maintain its upright growth and sturdy stalk. Thus, it has a hard and crunchy texture and is off-putting to most fish. However, the flowy crown filaments make nice hideouts and nesting spots.

Mermaid’s Fan (Halimeda Udotea)

  • Care Level: Moderate to difficult
  • Growth Rate: Slow
  • Lighting: High
  • Water Parameters: 72-78°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.025 SG
  • Supplementation: CO2, Calcium, Iron, Magnesium, Trace minerals

The Mermaid’s fan is a great midground and foreground plant. It also makes a good choice for medium to small aquariums. It grows very slowly, so you won’t have to trim it regularly. It can reach a maximum size of 1 foot high, but this will take a while.

This species is so simple yet charming looking. When purchased, it comes in a 3-4” size and looks like a small fan or fishtail sticking out of the substrate. It does best in a deep sandy substrate and requires sturdy anchoring. Although Mermaid’s Fan has moderate CO2 needs, it’s still not beginner-friendly.

This plant needs high light exposure and calcium and can be sensitive to high nitrate concentrations. Moderate and fast-growing plants often outcompete and starve the slow-growing Mermaid’s Fan.

So, you must choose the other plants carefully if keeping multiple species. On the flip side, the Mermaid’s Fan is reef-compatible and unlikely to get eaten by herbivorous fish. It’s also cute when the fish hide behind the leaf, so there’s that.

Blue Hypnea Algae (Hypnea pannosa)

  • Care Level: Moderate
  • Growth Rate: Moderate
  • Lighting: High
  • Water Parameters: 72-78°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.025 SG
  • Supplementation: CO2, Iron, Magnesium, Iodine, Trace elements

This is one of the most beautiful macroalgae. Blue Hypnea has a rich, vibrant iridescent blue color that you won’t find in any other aquatic species. It grows small and fine forked branches and forms dense, bushy clumps. Hypnea spreads outwards and anchors itself to coarse-grain substrates.

It looks excellent in the foreground and midground of the aquarium. It doesn’t grow very tall, so it’s well-suited even to smaller tanks. Blue Hypnea also works excellently alongside live rock thanks to its high phosphate and nitrate absorption.

Bottom-dwelling fish love this plant as it makes a cozy hideout. Another bonus is that most fish won’t nibble on this species. Despite its moderate to low supplementation needs, Hypnea needs strong light and grows very slowly, so keep that in mind.

Halimeda Algae

  • Care Level: Moderate
  • Growth Rate: Fast
  • Lighting: High
  • Water Parameters: 72-78°F, 8.1-8.4 pH, 8-12 dKH, 1.023-1.025 SG
  • Supplementation: CO2, Calcium, Iron, Trace minerals

Halimeda algae are also known as “cactus algae” thanks to their distinctive appearance. This macroalgae species grows upright into segmented filaments that resemble cactus pads. It grows up to 10 inches tall and fits well in most aquarium sizes.

Keeping Halimeda is a bit challenging because of its low nitrate tolerance. It also requires high calcium to maintain its rigid structure. Halimeda won’t filter waste by-products as effectively as other plants.

Still, it’s highly compatible with corals thanks to its high mineral and low toxin requirements. It’s a good addition if you want to beautify your aquarium with reef-safe plant species. Herbivorous fish are also unlikely to eat it because of its texture and bitter taste.

Benefits of Having Plants in a Reef Tank

Plants add interest to your reef aquarium. Tall macroalgae balance out the display by filling up the middle and upper layers, and the rich colors and foliage create a lush, natural look. But there are other reasons why plants are so good for your reef tank. In my opinion, the best thing about live plants is that they directly benefit the health of corals.

As any marine aquarist knows, maintaining proper water chemistry in a reef tank is like walking on eggshells. Corals are very sensitive to fluctuations in water alkalinity. Increases in CO2 and waste by-products like phosphates and nitrates, all too frequent in fish tanks, can drop the water pH and cause the corals to leech minerals into the water.

Luckily, live plants counteract this problem. Algae are the perfect sponges for phosphates, nitrates, nitrites, ammonia, and CO2. Their powerful filtering action helps you maintain stable water chemistry to the benefit of your corals.

Plants also benefit the fish in your reef tank. Through photosynthesis, algae transform CO2 into oxygen, keeping the water fresh for the fish. Bushy or tall plants provide hiding spots for small and shy fish. Lastly, some aquatic plants make healthy and nutritious snacks for herbivorous and omnivorous fish in the tank.

How to Grow Plants in a Reef Tank?

Growing plants in a reef tank is very similar to growing freshwater plants. Of course, there are a few tweaks. As most marine “plants” aren’t actual plants but macroalgae, some requirements will differ. Here’s a rundown of the basics:

– Choose the Right Substrate

Unlike true plants, macroalgae lack roots. Instead of anchoring themselves deeply into the soil, algae use holdfasts to fix themselves on top of the seabed. This will influence the type of substrate you should use in the tank.

For most macroalgae, a large-grain, rocky substrate is best. However, this isn’t true for all species. Always read the species factsheet carefully before buying plants.

– Maintain Appropriate Water Parameters

All aquatic species thrive in slightly different water parameters. What works for one species might not work for another. The most important values include temperature, pH, and water hardness levels. Keep an eye out for these and ensure they’re within a tolerable range for the plants in your tank.

Water parameters are equally important when choosing compatible species. Always check the species factsheet before adding new plants to the tank. Although some plants look stunning, they may not survive in your tank setup.

– Provide Adequate Lighting

Poor light conditions can lead to stunted growth and lackluster coloration. If you want your plants to thrive, you must ensure adequate lighting. Once again, this will differ from one species to the next.

Green algae typically thrive in intense light. Red-colored algae need medium light. Do your research first to figure out what works best for your plants.

– Monitor and Supplement Nutrients When Necessary

Besides light, plants need nutrients to grow and stay healthy. This includes CO2 and minerals. Most marine plants, in particular, need plenty of calcium, phosphate, iron, iodine, and magnesium. You may even need to supplement nitrates if the levels in the tank are too low!

Without these important nutrients, marine plants might lose their rich coloration. Severe deficiency leads to stunted growth and even death. I know, it’s scary— adding phosphates and nitrates to a reef tank sounds insane.

But trust me, your plants will thank you. Besides, the quantities you get from fertilizers aren’t high enough to negatively impact corals. The plants will soak up all the nutrients before you’d get a drop in water pH.

– Trim the Plants Regularly (If Needed)

Fast-growing plants need regular trimmings for multiple reasons. First, the more the plants grow, the higher the nutrient demand. Large plants tend to soak up all the nutrients in the water, starving smaller and slower-growing plants. Calcium-hungry macroalgae might even overtake your corals and steal all the minerals!

Secondly, trimmed plants look better. Letting the algae go wild and spread everywhere will make viewing the fish more difficult. Overgrown midground plants also obscure the back of the aquarium, making the tank look small and crowded.


Marine plants are less discussed than freshwater ones. But they bring just as much diversity and provide some of the same benefits. The right saltwater plants will help you control water pH and pollutants, making the aquarium safer for corals. If you’re unsure where to start, the plants in today’s article make excellent choices.

Beginner-friendly plants like Sea Lettuce, Green Finger algae, and Hair Brush algae are easy to find, grow, and maintain. Other plants on the list are more challenging but beautiful and rewarding nonetheless. Let me know which one’s your favorite!

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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