Best Aquarium Plant Fertilizers in 2021: Reviews with Comparisons

Best Aquarium Plant Fertilizers in 2021: Reviews with Comparisons

Living plants make an aquarium more beautiful and can contribute to the health and happiness of your fish. However, providing nutrients for your fish and maintaining healthy water doesn’t always create the nutrient balance that promotes healthy plants. Using an aquarium plant fertilizer can help care for your aquatic plants without harming your water quality. Here are some of the best aquarium plant fertilizers.

Best Aquarium Plant Fertilizers Reviews

API LEAF ZONE Freshwater Aquarium Plant Fertilizer 16-Ounce Bottle

API LEAF ZONE is explicitly formulated for lush, fast-growing, healthy plant leaves in a freshwater aquarium. It has chelated iron and potassium to aid in photosynthesis and healthy plant cell growth in a form that is quickly and easily absorbed by aquarium plants.

API LEAF ZONE prevents leaf yellowing and decay while promoting faster growth and vivid color in aquarium plants. It contains 3.00% soluble potash for potassium and 0.10% chelated iron. Plus, it will not harm fish and is easy to use weekly for improved plant health and growth. It is also easy to use weekly with the dosing cap on the bottle.

LEAF ZONE is designed to nourish and promote beautiful, healthy leaves in freshwater aquarium plants. It should be used in combination with a substrate or other product that also provides nutrients for healthy roots and stems.

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Seachem Flourish Freshwater Plant Supplement

Seachem Flourish Freshwater Plant Supplement nourishes and promotes healthy roots and shoots in aquarium plants. It contains phytohormones, minerals, and plant nutrients that promote photosynthesis, mobilize nutrients and improve stress responses.

Regular use helps plants resist disease, grow strong roots, and grow leaves and stems more quickly. It is also safe for fish and aquatic organisms.

Seachem Flourish Freshwater Plant Supplement contains phosphate, potash, calcium, magnesium, iron, and other trace minerals that plants need for healthy roots and rapid growth. The advanced formula is comprehensive for aquarium plant needs without harming fish, shrimp, or other tank inhabitants.

Seachem Flourish was created to provide phytohormones and trace minerals for aquarium plants. Plus, it does not contain the levels of potassium, nitrogen, and phosphorus found in most all-purpose plant fertilizers. This makes it safe for fish, shrimp, and other marine life, by not affecting nitrogen or phosphorus levels in a fish tank.

However, it also means that you may want to use a different product to increase the basic three elements all plants require.

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Aquarium Plant Root Fertilizer Tabs

These Aquarium Plant Root Fertilizer Tabs from Planted Aquarium Concepts are designed to nourish the roots of your aquarium plants by slowly releasing nutrients into the substrate. They are easy to use; simply bury the tablets in your gravel or substrate near the plant roots, and replace them every three months.

The slow-release formula prevents sudden changes in water chemistry, and the tabs provide plant nutrients right at the roots, where they are needed most.

Planted Aquarium Concepts’ Aquarium Plant Root Fertilizer Tabs contain nitrogen, phosphate, potassium, calcium, magnesium, sulfur, and other essential plant nutrients, in higher levels than many other fertilizer tablets.

They have no copper, so they are safe for shrimp and other aquarium species. They are also less inclined to float than other tabs, making them easier to use and better for plant roots.

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Thrive Aquarium Liquid Plant Fertilizer

Thrive Aquarium Liquid Plant Fertilizer from NilocG Aquatics is an all-in-one, easy-to-use, highly concentrated aquarium plant fertilizer. It contains all the micro- and macro-nutrients that planted aquariums need for healthy, thriving plants.

The Thrive Aquarium Liquid Plant Fertilizer is incredibly convenient to use, with a simple pump bottle. The concentrated formula allows you to treat up to 2,500 gallons of aquarium water with a single bottle.

It’s helpful in low- and high-tech planted aquariums and will not harm fish, shrimp, or other aquatic species. It contains nitrogen, phosphate, potash, magnesium, calcium, sulfur, iron, and other trace minerals necessary for healthy plant growth. In addition, it’s backed by a 100% satisfaction guarantee.

Because this formula is high in nutrients and highly concentrated, it’s a good idea to begin with a lower dose, especially if you also have a nutrient-rich substrate.

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Aqueon Aquarium Plant Food

Aqueon Aquarium Plant Food contains all the macro, and micronutrients freshwater plants need to live and thrive, along with kelp extract to promote healthy root growth. The convenient dosing cap makes it easy to use, and it’s an all-in-one product.

Aqueon is one of the most trusted brands in fish tank care, and their aquarium plant food is a great all-in-one supplement for healthy plants. It contains potash, calcium, magnesium, sulfur, and other trace nutrients for plants, in a formula that is safe for fish, snails, and other aquatic organisms.

In addition, it has kelp extract to promote healthy roots, and it’s easy to adjust the dosage depending on your needs. It’s also more affordable than many aquarium plant fertilizers.

Aqueon Aquarium Plant Food is a plant “food,” not a fertilizer; it has all the nutrients that plants need, but in lower levels that have less impact on water chemistry. It’s designed to be used more like a “food” added to your tank in small doses throughout the week to keep plants healthy.

If you have more plants and want faster growth, increase the amount used. If you simply want to keep your plants healthy, feed once a week.

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Buyer’s Guide

Like terrestrial plants, aquatic plants grow more and better when they have the right balance of nutrients. Here are some things to look for in an aquarium plant fertilizer.

Nutrient Balance

All plants require nitrogen, phosphate, and potassium (NPK) to grow well, and terrestrial plant fertilizers are typically rated by the amounts and ratios of these three essentials. However, aquariums are more delicate ecosystems, and adding nitrogen to the water may not always be desirable.

As with all plant fertilizers, more is not always better because the needs of your plants must be balanced with the requirements of fish, bacteria, shrimp, and other species in your tank.

If you use a nutrient-rich substrate for your plants, your aquarium plant fertilizer may not need high NPK values but instead need micronutrients and trace elements that don’t last as long in the water column.

Read the labels carefully to determine levels of essential nutrients in the plant food or fertilizer; consider any existing nutrients or elements in your substrate, and start with lower dosages of fertilizer to determine what is best for your fish and your fish tank.

Copper Levels

All the best aquarium plant fertilizers have extremely low or no copper, so they are safe to use in tanks with shrimp, snails, and other aquarium species. However, it’s always a good idea to check the label carefully and review copper levels or determine whether your aquarium plant food is safe for all your marine species.

Algae Growth

Excess plant nutrients, particularly aquarium fertilizers high in NPK, often cause excess algae growth. Just like overfeeding fish can cause a tank to get dirty more quickly, overfeeding plants can cause unwanted algae blooms. To avoid unwanted algae growth:

  • Use tablet fertilizers instead of liquid
  • Reduce plant fertilizer dosage
  • Choose a plant fertilizer lower in NPK

Liquid or Tablets

Aquarium plant fertilizers come in liquid or tablet form. Liquid fertilizers should be added to the water to allow plants to absorb nutrients from the water.

Tablet fertilizers are designed to be buried in the substrate to nourish the plant roots with less impact on the water balance. Here are some guidelines for choosing the right aquarium plant fertilizer for your needs:


No plant can live and thrive without healthy roots. Providing extra nutrients in the soil helps to strengthen and nourish the entire plant. When considering tablets, keep in mind:

Inert Substrate

If your substrate is already rich in plant-boosting nutrients, you probably don’t need tablet fertilizers. However, if you have an inert substrate, tablets are probably a good idea.

Old Substrate

As plants grow, they consume the nutrients present in the substrate. Old substrate isn’t as beneficial for plant roots, but replacing substrate can be a time-consuming process. If your substrate is old, you may want to add tablet fertilizers to feed your aquatic plant roots.

Water Chemistry

Suppose you have delicate water chemistry and want to feed your plants with minimal impact on the balance of your water. Then, tablets are an excellent way to provide plant-specific nutrients without adding extra elements that may affect your water.

Algae Growth

If you have a problem with algae, tablets are a better way to feed your desired aquascape plants without providing excess nutrients for algae.


While all plants require the big three NPK, aquarium plants also need other trace nutrients and micronutrients for improved health. You may want to use a liquid fertilizer or plant food when:

You Want to Boost Leaves and Shoots

If your plants are healthy overall, but you want more vibrant, faster-growing leaves and shoots, liquid fertilizer can provide nutrients targeted for above-ground growth rather than simply nourishing the roots.

Soluble Elements

Tablets are slow-dissolving and release vital, more durable nutrients to plant roots. However, some essential plant nutrients are not as stable and long-lasting and won’t persist in the water for long periods. Liquids provide some of these nutrients with a shorter lifespan and are better absorbed by leaves from the water column than by roots in the substrate.

Ease of Use

Nothing can be simpler than just adding a capful of liquid fertilizer to your aquarium periodically, feeding your plants as quickly and easily as you feed your fish.

Whole Plant Care

For a truly healthy aquascape, it’s essential to care for the entire plant. Aquarium plant food and plant fertilizers are an important factor but only part of the picture. Here are all the other factors to consider:

Plant Roots

Do your aquarium plants have essential nutrients and a healthy environment at the roots? Have you chosen a high-quality substrate? Do you need to supplement with fertilizer tablets?

Plant Leaves and Stems

Are your plant leaves healthy, vivid in color, and growing well? You may want to add liquid fertilizer to boost leaf health.


Aquarium plants cannot grow properly without adequate light levels. Slow growth, poor color, and weak leaves are often caused not by a lack of nutrients but by a lack of light.

Water Quality

Most freshwater plants, just like fish, do better in water with healthy pH and CO2 levels, at the right temperature, with a clean tank and regular water changes.

Keep in mind that many water conditioners specifically remove heavy metals, and therefore may remove some of the trace minerals in your fertilizer. Maintaining healthy, balanced water is just as crucial for your aquarium plants as it is for your fish.


How to use Aquarium Plant Fertilizer?

As a rule, you should always use aquarium plant fertilizer according to the manufacturer’s instructions. However, if you are a beginner or have a delicate tank, it’s not a bad idea to start slowly, with half the manufacturer’s recommended dosage. But, if you only have a few plants, the recommended dosage may be too high for your fish tank.

Under-dosing also prevents rapid water changes that may be harmful to other aquarium inhabitants and lets you customize your usage for the specific needs of your plants.

To use liquid aquarium plant fertilizers, you can usually add them to your aquarium water periodically or add them during water changes. To use aquarium plant fertilizer tablets, bury them in the substrate near (but not touching) your plant roots, and replace them periodically.

Is Aquarium Plant Fertilizer Safe for Fish?

Yes, aquarium plant fertilizer is safe for fish. However, if you choose a fertilizer that is high in nitrogen, it may be a good idea to introduce it gradually to maintain the water balance in your tank.

All our preferred aquarium plant fertilizers are also safe for shrimp because they contain extremely low levels of copper or no copper at all. If you have shrimp or other aquatic species in your fish tank, read the label of an aquarium plant fertilizer carefully to make sure it is safe to use in your tank.

You may also want to gradually introduce aquarium plant fertilizer to make sure your tank and fish remain healthy and happy.

Do I Need Aquarium Plant Fertilizer?

All plants need nutrients to grow. However, if you have used a long-lasting, nutrient-rich substrate, your water is balanced, and your plants look healthy, you may not need to use supplemental plant food or fertilizer. Some popular aquarium plants don’t need fertilizer at all, deriving all of their nutrition from fish waste, including:

– Java moss
– Java fern
– Water wisteria
– Anacharis
– Asian Ambulia
– Hornwort

However, even these hardy species will likely benefit from supplemental nutrition, even if they don’t need it to live.

Most aquarium plants eventually need supplemental nutrition in the form of fertilizer because substrates eventually exhaust their nutrients or because some plants need trace elements from the water column rather than the soil; the right amount of plant food will make all aquatic plants grow faster and healthier.

Which is More Important: Fertilizer or Substrate?

A healthy, nutritious substrate is the best way to care for aquarium plants. Start with an excellent substrate, then ensure that your tank has good light and CO2 and pH levels.

Replace the substrate as recommended by the manufacturer, and the substrate and fish will provide almost all the care your plants need. If you have a lightly planted tank and an excellent substrate, you might need to use plant food or fertilizer.

However, heavily planted tanks should usually be supplemented with plant food or fertilizer because dense planting depletes nutrition more quickly.


For beginners with an inert or poor substrate, Aquarium Plant Root Fertilizer Tabs is the best choice. They are easy to use and only need to be replaced every 3 months.

They nourish plants at the roots, where nutrients are needed most, and have a reduced effect on your overall water quality. This means there’s no risk to fish or other aquarium inhabitants. It’s a simple, easy way to nourish your aquarium plants for a long time with less fuss.

For general use, the Aqueon Aquarium Plant Food is the best all-purpose plant fertilizer for aquarium plants. It provides all the trace nutrients and micronutrients that plants need in the water column, with less risk of overdose or affecting aquarium water too much.

In addition, it’s safe for all fish tank inhabitants, easy to use, and affordable. Aqueon is a trusted brand, and this plant food is a great way to simply and safely help your aquarium plants grow faster, improve health and color, and look great even in lower light conditions.