Best Substrate for Discus

Posted by Miles Harrison on 01/26/2022

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Discus fish, some of the most colorful freshwater fish in the world, are a challenging but rewarding stocking option for a freshwater aquarium. Discus are highly sensitive to ammonia, nitrite, water quality, and changes in water temperature. If you decide to take on this species, you'll want to make sure you've done extensive research. In this article we'll recommend options for what will likely be one of your first choices, picking the right substrate.

Image of a Red Discus
Discus, native to the Amazon river basin, have some of the most striking color features

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Our Top Picks

Best Overall: FairmountSantrol AquaQuartz-50 Pool Filter 20-Grade Silica Sand 50 Pounds

FairmountSantrol AquaQuartz Pool Sand Filter is our favorite choice overall. This Sand Filter won't alter Nitrate levels, which must be less than 10ppm for Discus fish. This sand also can be cleaned easily with a standard gravel cleaner.

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Runner-Up, Best Overall: CaribSea Super Naturals Aquarium Sand

This aquarium sand is ideally sized and shaped for preventing the accumulation of detritus, fish waste, and food in the substrate while remaining fish friendly. Although slightly more difficult to vacuum with a gravel cleaner, this sand is a great alternative to pool filter sand.

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Best for Planted Aquariums: FairmountSantrol AquaQuartz-50 Pool Filter 20-Grade Silica Sand 50 Pounds mixed with CaribSea Eco-Complete 20-Pound Planted Aquarium, Black

Layering Eco-Complete with Pool Filter Sand gives you the best of both worlds. The Discus benefit from the filter sand and plants can attach their roots to the Eco-Complete gravel, making it our number one choice for a planted Discus tank.

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Runner-Up, Best for Planted Aquariums: CaribSea Eco-Complete 20-Pound Planted Aquarium, Black

CaribSea's Eco-Complete is the gold standard for planted tanks, so it's no surprise it's topped our list for Discus fish. Eco-complete is a great gravel substrate that will allow your plants to grow and thrive without harming your fish

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Best Budget Option: Landscape Rock & Pea Gravel

Pea-Gravel makes for a natural-looking substrate while keeping the wallet light. Often sold by the cubic foot, pea-gravel can be an excellent substrate choice for a Discus tank.

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Pool Filter Sand

Our number one choice is Pool Filter Sand. Since Discus will adapt to their environments by camouflaging, a light-colored substrate will help prevent peppering and color change. Pool Filter Sand is easy to clean, and with the addition of root tabs, can be used to grow aquatic plants. This sand from FairmountSantrol is 100% natural, chemical-free, and ecologically safe.

FairmountSantrol Pool Filter Sand
FairmountSantrol Pool Filter Sand

CaribSea Eco-Complete

If you've had a planted aquarium before, chances are you have already heard of CaribSea's Eco-Complete. Considered by many to be one of the best substrates, this natural-looking gravel contains no dyes, paints, or coatings. Eco-complete does contain minerals like iron, calcium, magnesium, potassium, and sulfur. If you're new to Discus, we recommend you monitor your water chemistry when working with eco-complete. When fully matured, this substrate is great for plant roots. We recommend rinsing this substrate before use due to the sensitivity of Discus fish.

Image of CaribSea Eco-Complete substrate bag
CaribSea Eco-Complete

CaribSea Super Naturals

CaribSea's Super Naturals is a pH-neutral substrate that won't increase carbonate hardness. Its smooth grains are fish friendly and perfect for Discus or other bottom-dwelling fish. This sand does tend to move around, and will occasionally get sucked up during water changes. If pool sand isn't available, this is a good alternative.

Image of a bag of CaribSea Super Naturals substrate
CaribSea Super Naturals is a good alternative to Pool Filter Sand

Pea Gravel

Pea Gravel is a pH neutral gravel that pairs well with Discus. Often sold by the cubic foot, this budget-friendly gravel gives a natural look to any Discus tank. Due to the gravel size, plant roots should be able to take hold but will need additional nutrient dosing.

Image of a bag of KolorScape pea gravel
KolorScape Pea Gravel is an affordable substrate option

Pool Filter Sand combined with Eco-Complete

Although a bit pricy, combining Pool Filter sand with Eco-Complete is our favorite suggestion for a planted Discus tank. Adding pool filter sand to the front of the tank, and sloping the sand towards the back of the tank over a layer of eco-complete gives the best of both worlds. Chemistry levels remain stable, but underneath the sand, your plants will be able to establish roots around the eco-complete gravel. Since eco-complete is nutrient rich, we recommend rinsing this substrate before use.

Image of a pool filter sand combined with eco-complete
Pool Filter Sand works well with Eco-Complete


These substrates are some of our favorites for Discus keeping. Discus are a difficult species to provide a healthy environment for, but by picking one of these substrates, you'll have a great foundation to set yourself up for success.

Thanks for reading!