The 4 Best Aquarium Plant Substrates of 2024

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A collage of aquarium plant substrates we recommend on a colorful background

The Spruce Pets / Chloe Jeong

The material on the floor of a fish tank is referred to as the substrate. It typically has a gravel-like consistency and its primary role in an aquarium with live plants is to provide a nutrient-rich foundation where roots are able to flourish.

Depending on the type of water-dwelling plants and creatures you plan to care for, the right planted aquarium substrate should help you maintain the optimal pH level, which we recommend checking on a monthly basis for safety. The substrates we selected are all self-sufficient for plant life, offering the beneficial bacteria needed for the essential nitrogen cycle, and providing micro- and macronutrients your plants need to thrive.

Our Top Picks

Best Overall

CaribSea Eco-Complete Planted Aquarium

CaribSea Eco-Complete Planted Aquarium Substrate, 20-lb bag

Chewy

What We Like
  • The substrate is biologically complete and does not require a second substrate

  • Contains no artificial dyes

  • Made with nutrient rich volcanic soil

What We Don't Like
  • For aesthetics, you may find it necessary to add a second non-carbonate substrate

CaribSea Eco-Complete Planted Aquarium Substrate is primarily composed of basaltic volcanic soil, which has a high granular absorbency that helps promote optimal nutrient uptake to a plant's roots. It also has the bacteria necessary to maintain your aquarium's internal nitrogen cycle, in addition to 25 other micro- and macronutrients that are beneficial for plants, including iron, calcium, magnesium, potassium, and sulfur. While supplemental fertilizer will eventually be necessary, Eco-Complete will provide the right start to your planted aquarium.

There's no need to rinse Eco-Complete in advance, simply fill the bottom of your tank to a depth of approximately three inches. The CaribSea substrate contains both fine and large grains, which will eventually settle into two separate layers, with a finer bottom providing hold for your plants' roots. While you always have the option of a second substrate layer, such as one selected as an aesthetic cover, it's not necessary when using Eco-Complete, which has a neutral black tone.

CaribSea's Eco-Complete contains no artificial dyes. It is additionally free of nitrate and carbonate, so it won't alter the hardness or pH values of your aquarium water. It is available in a 20-pound bag.

Type: Gravel | Weight: 20 pounds | Colors: Black

Runner-Up, Best Overall

Seachem Flourite

Flourite, 7 kg / 15.4 lbs

Amazon

What We Like
  • Chemical-free formulation will not alter the pH of a tank

  • Suitable for standalone use

  • Available in two colors, black or red

What We Don't Like
  • Mechanical filtration for removing cloudiness may be required

Seachem Flourite is a porous clay substrate rich with nutrients plants need to flourish, particularly iron. In a freshwater aquarium, this substrate can be used on its own without the need to layer an additional substrate. It's also suitable for use with a decorative layer of substrate to achieve your desired appearance in a tank.

The formula is chemical-free, ph neutral, and available in two colors, black or red. It's pre-rinsed, but we recommend rinsing in the bag before placement in a tank to reduce the intensity of cloudiness. For many using this Seachem Flourite substrate, mechanical filtration with a filter floss is needed to dissipate particles after the initial installation.

Type: Gravel | Weight: 15.4 pounds, 7 pounds | Colors: Black, red

Best for Live-Planted Aquariums

Fluval Plant and Shrimp Stratum

Fluval Plant and Shrimp Stratum, For Fish Tanks, 4.4 lbs., 12693

Amazon

What We Like
  • Allows plant roots to spread as needed

  • Suitable for use with shrimp and will camouflage newborns from fish

  • Provides active bacteria and nutrients needed to maintain pH and remove naturally-occurring ammonia

What We Don't Like
  • Not suitable for use with large or boisterous fish

  • Not recommended to mix with an additional substrate, even for decorative use

For a freshwater live planted aquarium, Fluval Plant Stratum is a lightweight porous substrate that will facilitate plants and their roots to grow and spread without compacting or blocking their organic shape.

It contains essential nitrifying bacteria to reduce ammonia and maintain a neutral to slightly acidic pH that will not discolor the water. It has a small grain size and coloring that is suitable for use in a tank with snails and shrimp. For shrimp particularly, the texture and color allow them to hide and camouflage newborns from fish. However, this substrate is not recommended for large or boisterous fish, such as large cichlids, nor is it intended for use in brackish tanks, which mixes fresh and salt water.

For installation, Fluval Plant Stratum should be lightly rinsed to remove loose dust. Initial cloudiness should dissipate after a few hours, and the environment is safe for fish and shrimp even during the cloud stage. Fluval Plant Stratum comes packaged in 4.4-, 8.8- and 17.6-pound bags. A single 4.4-pound bag is suitable for tanks under 18 inches, an 8.8-pound bag is suitable for 18-inch tanks, and the 17.6-pound bag will cover a 24-inch aquarium.

Type: Gravel | Weight: 17.6 pounds, 8.8 pounds, 4.4 pounds | Colors: Dark brown

Best for Nitrification

Activ-Flora Aquarium Substrate

Activ-Flora Lake Gems for Aquarium, 20-Pound

Amazon

What We Like
  • Nutrient-enriched gravel

  • No artificial dyes or additives

  • Contains iron so no additional need for laterite clay under gravel

What We Don't Like
  • Cloudiness after initial install may last several hours

Nitrification is the process of removing naturally occurring ammonia from water to support a healthy environment for fish to swim. With the help of active heterotrophic bacteria, Activ-Flora Planted Aquarium Substrate facilitates this organic process. It's a specialized gravel with essential minerals and micro-nutrients including phosphorous, magnesium, potassium, copper, and zinc, and it's pH neutral. The iron-rich formula can be used as the sole substrate without the need to layer laterite clay substrate underneath for plants to grow.

The substrate is pre-washed, so it can be placed directly into your tank, but you may experience cloudiness for several hours. With this substrate, there is no ongoing need to clean or even replace it for the duration of your tank. If the substrate is agitated, loose particulars will likely begin to float but your filter system should remove the cloudiness. It's available in several grain sizes and colors for use in a variety of applications.

Type: Gravel | Weight: 20 pounds | Colors: Floragems, lake gams, black

Final Verdict

Our top pick for freshwater aquariums is CaribSea Eco-Complete Planted Aquarium Substrate. It's made with nutrient-rich volcanic soil, contains no artificial dyes, and can be layered with a decorative substrate if desired. If you have a tank with plants, shrimp, and snails, we recommend Fluval Plant Stratum. The texture and coloring allow plant roots to thrive and will camouflage baby shrimp from fish until they are old enough to co-exist.

What To Look For

Neutral pH

A pH of 6.8 to 7.2 is ideal for most aquariums and the substrate you select should help you maintain a neutral level. We recommend checking your tank's pH level once a month to avoid algae growth from low pH levels or excess ammonia from a high pH, which can be fatal for many fish.

If you have hard water, meaning the water from your faucet contains high quantities of microscopic minerals like calcium and magnesium, then you might benefit from our Best for Nitrification selection, Activ-Flora Planted Aquarium Substrate, which contains active heterotrophic bacteria to reduce the levels of naturally-occurring ammonia.

Nutrients and Minerals

For plants to thrive in an aquarium, the substrate must provide a mix of nutrients and minerals including iron, phosphorous, magnesium, potassium, copper, and zinc. The substrates we selected are all self-sufficient and do not need to be combined with an additional layer.

Coloring

Many self-sufficient, nutrient-rich aquarium sands are black, dark brown, or reddish in appearance. Depending on the substrate you select, you may be able to add an additional substrate for decorative use, but we recommend avoiding substrates with artificial chemicals and dye.

Amount Needed

The substrate for live plants that you select will offer guidance on the amount you need to put in your aquarium. Generally speaking, deep-rooted plants require two to three inches of substrate.

Why Trust The Spruce Pets?

This article was written by Shirlie Sharpe, a fish and aquarium expert who has written a book on setting up an aquarium. For additional background on aquarium plant substrates, we spoke to Nic Tiemens, co-founder of Infinity Aquarium Design, who advised us on what to look for in substrates.