The Best Aquatic Fertilizers – Buyers Guide

aquarium plants

The right question should be does your aquarium need fertilizer, the answer is yes and no.

Yes because your plants need nutrients that may not be readily available and have to be sourced from somewhere else. Apart from light and water the substrate in the fish tank rarely contains the necessary nutrients needed for your plants to thrive. 

No? That’s puzzling, well there are those aquarium plants that are self-reliant and overtime have mastered survival skills. They are thus able to thrive without using fertilizers, the likes of the Marimo moss balls and the java fern.

Choosing the best fertilizer

Most important is the ability of the aquatic animals in your aquarium to tolerate the fertilizers, remember knock-offs don’t lack in every market, so if you are not going to find something legit from the vet, it would be best to keep off and adopt plants that can do well without the extra nutrients provided by the fertilizers. 

On a serious note, your aquatic plants need fertilizers, some of the nutrients like nitrogen and phosphorus can be obtained from waste and fish food, but other minerals have to be added to the aquarium from time to time. Other nutrients providing minerals like iron, magnesium, potassium, and manganese are necessary for healthy plants. 

The best types of fertilizers should be water-soluble and can be added when changing the water in the fish tank. A rule of thumb is that you use a weak solution, of one-quarter the strength that has been recommended. Choosing the best fertilizer is not easy especially for newbie’s, and that is why we compiled a list of the best aquatic fertilizer that is right for your aquarium.

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The API leaf Zone is a great solution for your aquatic plants, one because it won’t hurt your fish, promotes the growth of your plants as it is easily absorbed in the leaves of the plant. The fertilizer will also ensure that your leaves are lush green as it contains chelated potassium and iron.  It is best suited for use in aquariums that are inhabited by freshwater plants and fish. 


  • Gentle on fish 
  • Easily absorbed by plants
  • Helps stimulate colorful leaves
  • Soluble in water


  • Contains small portions of nutrients
  • Too much use may negatively affect the plants

2. Thrive Aquarium Plant Fertilizer

Thrive Aquarium Plant Fertilizer

The thrive aquarium will provide your plants with both the micro and macronutrients, what’s more, is that it has the capability of treating up to 2500 gallons of aquarium water with one 500ml bottle. It is effective in the prevention of algae growth and keeps plants from dying. 

The fertilizer is contained in an easy to use pump bottle, which simplifies the process of fertilizer application. 


  • Contains all the micro and macronutrients
  • Effective for both the high and low tech aquarium setup 
  • Can be used in large fish tanks 
  • Helps in stopping the growth of algae


  • Could lead to high nitrate concentration in water
  • Is highly-priced compared to others of the same standard in the market

3. Seachem Flourish

Seachem Flourish

The seachem flourish is known for enhancing the growth of the roots and shoot of your aquatic plants, this is because of the presence of phytohormones, nutrients, and minerals in its constitution. The phytohormone is necessary for advancing a variety of development processes such as the formation of shoot meristems, the induction of photosynthesis gene expression and nutrient mobilization among others. 

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The fertilizer is also effective in mineral absorption and enables the plants to be disease resistant. Upon application flourish will work on the roots of the plants to enhance their growth. From then on, you will witness significant growth in the leaves and stems of plants. The fertilizer can be applied on a daily basis and it is completely safe for plants and other aquatic organisms. 


  • Can be used on different fish species
  • Does not alter tank water chemistry 
  • Encourages growth from the roots
  • Contains the necessary micronutrients 


  • Too much usage could lead to the growth of algae
  • The caps do not fit tightly

4. Glosso Factory All in one

Glosso Factory

The Glosso Factory Aquarium fertilizer is an all in one fertilizer efficient for planted aquariums. Its constitution has incorporated the use of both the macro and micronutrients. Usability is guaranteed as it comes with clear instructions. The fertilizer works effectively with regular water changes. Incase algae start to bloom, you are advised to reduce dosage or increase the water changes. 


  • Easy to use as it comes provided with instructions
  • The constitution is a balance of micro and macronutrients
  • Works well in low tech tanks that harbor invertebrates
  • Can be used with all types of aquarium plants 


  • Not recommended for use with a dosing pump
  • Nozzle breaks of quickly

5. Luffy Marimo Fertilizer

Luffy Marimo Fertilizer

The Luffy plump fertilizer has been specially made to cater to the Marimo Moss Balls, you can, therefore, expect you moss balls to get a dose of calcium, nitrates, and phosphates. Your marimo will, therefore, grow quickly and present a rich color; they will also grow big and fluffier. Apart from providing nutrients to the moss balls, the fertilizer will also enrich the lives of the other plants in your aquarium. 

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This is so because of the phosphates, calcium, and nitrates present in the fertilizer constitution that is usually used by other aquatic plants. The application of fertilizer to your moss ball is easy, as you will first have to squeeze your moss mall in preparation for the incoming nutrients and then put a few drops once every week. 


  • Adds unavailable nutrients to the moss ball
  • Not harmful to other aquatic animals
  • Encourage a greener and healthier moss ball
  • Makes the Marimo balls more fluffy


  • Fertilizer container not very sturdy
  • Takes time before you see the results


The use of fertilizer in an aquarium is necessary if you want the cosmetic look; besides some of the nutrients are not readily available and can only be found in fertilizers. So before you purchase one, consider the type of plants that you have, for example, you might want to purchase a different one for the moss balls. All in all, the above-sampled fertilizers will not harm the dwellers of your aquarium and are easy to use.

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