Aquarium plant deficiencies arise when the level of nutrients or environment is insufficient to ensure healthy plant growth.

Apart from the basics like sunlight and PH levels, the plants require close monitoring and care. If you notice the aquarium plant leaves turning yellow or brown, something is not right.

Read this article and learn the different deficiency signs your aquarium plant exhibits — what they mean and how to fix the problem.

Aquarium Plant Deficiencies

An aquatic plant deficiency points to a lack of crucial plant nutrients. Aquarium plant nutrients are essential as they ensure plant growth.

Below we have classified the plant nutrients into two kinds:

  1. Mobile aquarium nutrient
  2. Immobile aquarium nutrient

1. Mobile Aquarium Nutrient

Mobile nutrients are the kinds that move around the plant. For example, the aquarium plant can transfer nutrients from older branches to help it grow new ones. It is the plants’ way of surviving and growing even when there is an obvious lack. It would cause the old leaves to develop a varied symptom of lack depending on the nutrient the plant moved.

Some mobile aquatic plant nutrients include nitrogen, zinc, magnesium, phosphorus, and potassium.

2. Immobile Aquarium Nutrient

Immobile plant nutrients are the kinds of nutrients the plant cannot redistribute from older leaves to its new growth. In this case, the new leaves would develop the lack of nutrient symptoms. Some examples of immobile plant nutrients are manganese, boron, iron, calcium, sulfur, and copper.

The bigger a plant gets, the higher amount of nutrients it would require. However, plants that grow slowly may take longer to exhibit deficiency symptoms compared to a fast-growing plant.

Signs of Plant Deficiencies

There are symptoms to look out for that narrow down the nutrient your aquarium plant lacks. If you do not pay attention to the signs, it can lead to massive destruction of the plant and tank ecosystem. However, it is essential to know that one deficiency can lead to the plant not accessing another nutrient. That can result in a series of nutrient scarcity.

– Aquarium Plant Potassium Deficiency

When your aquarium plants have a potassium deficiency, develop a yellow or brown edge and pin-like holes in aquarium plant leaves. The yellowing is due to iron chlorosis and the potassium deficiency happens with reverse osmosis filters.

To tackle the potassium deficiency, add a fertilizer that contains potassium or potassium supplement regularly to your plant. If you have anubias and java fern, watch them closely as they need potassium to be healthy and likely to exhibit deficiency symptoms.

– Aquarium Plant Iron Deficiency

Iron deficiency in new leaves causes them to be darker than other leaves. Aquarium plants yellowing and green nerves in older leaves are caused by iron deficiency. Furthermore, the leaves become dry to touch and would rot and fall.

An iron deficiency arises from insufficient potassium levels, under or over-fertilization, high carbonate hardness levels, and PH. You can balance the iron levels by using an iron supplement or iron-infused fertilizer or substrate. Iron fertilizers would also cause a red-colored plant to appear darker but are not as efficient as supplements.

– Aquarium Plant Nitrogen Deficiency

Nitrogen deficiency is a common issue inexperienced aquarists face in their heavily planted aquarium. The beginner aquarist follows guidelines mechanical without really being observant. For example, they begin fishkeeping and hear about how important water changes are but forgetting testing for nitrate is also essential.

While clean water is great for the fish, if you keep flushing off all the nitrate, it will disrupt the tank’s nitrogen levels. In this case, fertilizers would not be enough to make it better.

Another underrated reason your aquarium plant is suffering from nitrogen deficiency is misinformation.

You get a plant and watch it grow using a certain fertilizer quantity, but you still use the same fertilizer measurement after some months with steady growth. As your fish pet grows, you increase their meals the same with the plants; as they grow, they need more nutrients.

In the same way, if you trim the branches of your plants, you will need to reduce the fertilizer or your nitrogen source. Try to balance the nutrient so as no to impede plant growth.

Signs of Nitrogen Deficiency in an Aquarium Plant

The older leaves begin to look yellowish, and you would almost see through the leaves, particularly the tips. As it is a mobile nutrient, the plant transfers the nitrogen content from the bottom to grow out the top until the old leaves die. In difficult situations, the new growth would also have yellow or whitish leaves.

However, not every yellowing or whitish leaf indicates nitrogen deficiency. In some cases, the plant is trying to acclimatize to its new home and living conditions. Other times, it can be the plants’ hobbyist you bought your aquarium plant from and grew a submerged plant species using an emerse method. So the leaves would have to melt to give room for healthy submerged leaves.

The melting plant would first shed its older or bottom leaves, causing the plant to look almost bare with only top leaves. You would have to patiently wait for a short period for the immersed plant to convert to a submerged plant. Afterwards, you must prune the healthy top and plant it in your tank as it is aesthetically pleasing and a smart decision.

“Anubias and java” fern are less likely to melt when you change their environment, unlike cryptocoryne, amazon swords, and other plants with stems. They would melt, shed, and end up looking bare with skinny stems before recovering.

– Aquarium plant Carbon Dioxide (CO2) Deficiency

Some Carbon Dioxide deficiency arises from poor care. Plants take in carbon dioxide, and it can be a struggle to ensure the aquarium has sufficient production. If the tank water is aerated intensely or the water is constantly agitated, carbon dioxide tends to escape into the air.

Signs of Carbon Dioxide Deficiency in an Aquarium Plant

  • You would observe the aquarium plant is not growing as fast as it should. It remains almost the size and smaller than a plant with sufficient carbon dioxide.
  • The plants’ leaves would have deposits containing calcium.
  • The Ph level would be disrupted, causing a sudden spike in the system.

To tackle the carbon dioxide deficiency, regulate the water agitation, aeration in the aquarium and use a carbon dioxide fertilizer. However, when there is excess carbon dioxide in the tank water, it affects both fish and plant. You would notice the fish has problems breathing and would come to the tank’s surface so that they do not suffocate.

Inspect the aquarium filter for dirt or the fertilization system if it is automated to regulate the excess carbon dioxide production. Adjust it, releasing just what the plants need by turning it off at night. Poor lighting is also a culprit, and oxygen efficiency and imbalanced fish load affect the carbon dioxide in a tank. Therefore, you need to check all the factors and make adequate changes.

– Aquarium Plant Calcium Deficiency

When you see the new leaves on your aquarium plants looking twisted and pale, then you know it has a calcium deficiency, manganese overload, or the low water hardness is affecting it. Sometimes, it’s a magnesium deficiency that causes the plant to grow in that manner.

To regulate calcium deficiency in your plant, you need to add supplements or salts that would reverse the nutrient shortage. Particularly for a soft water or reverse osmosis deionized aquarium, the salts would replenish lost nutrients and help your plants grow. Alternatively, add crushed coral to your filter or your substrate because it would help boost calcium nutrients and water hardness.

– Aquarium Plant Oxygen Deficiency

Oxygen deficiency causes aquarium plants to be stunted, and excessive algae growth would cover the tank. Furthermore, the oxygen shortage stalls the tank’s nitrogen cycle as the aerobic bacteria require oxygen to be efficient. In this case, the aquarium would content excess carbon dioxide, ammonia, and nitrates.

The primary cause of oxygen deficiency is when the plant has challenges absorbing carbon dioxide and cannot give off oxygen.

The solution to oxygen deficiency in aquarium plants

  • Inspect the tank filters
  • Also, check the aquarium lights to ensure it is sufficient
  • Balance the fish load as overpopulation is an issue
  • You should ensure you perform tests, routine maintenance and adjust, as necessary

– Aquarium Plant Phosphate Deficiency

Lack of phosphate deficiency causes yellow and brown coloration on old leaves. In extreme nutrient deprivation, the leaves die and shed off. Aquarium plants require large amounts of phosphate to grow. Algae may cover some portions of the leaves before it falls off; they feed off on the remaining nutrients and cause starvation. However, phosphate deficiency is rare because the fish feed has trace amounts of phosphate.

To tackle the phosphate loss and stop aquarium plants browning, impede algae growth by placing pad filters in the tank filter. However, when there are excessive phosphate productions, like the deficiency, it turns the leaves dark brown or black. When the nitrate in the water is in excess, the aquarium will suffer algae blooms.

When you do not perform regular water changes, or the aquarium water is insufficient, then your tank would have high phosphate levels. You must schedule regular maintenance and follow it through.

– Aquarium Plant Manganese Deficiency

When an aquatic plant has manganese shortage, its leaves will become yellow, but the nerves remain green. It arises in plants that have its iron fertilization not balanced. Ill care, wrong substrate choice and poor lightning are all issues that affect the nutrient lack. To fix the deficiency, use a fertilizer that has all the nutrients the plant requires.

– Aquarium Plant Magnesium Deficiency

Like in iron and manganese deficiency, a magnesium deprived leaf has deep colored nerves and bright tissue. However, the difference is the lack happens in old leaves, not the new ones. As the deprivation intensifies, the leaves lose vigor and begin to develop droopy edges.

To rectify the issue, increase your fertilizer dosage because most brands are magnesium enriched. Use magnesium supplement and special salts to increase its levels.

– Other Causes of Aquarium Plant Deficiencies

а) Substrate Issues

When the substrate is too smooth, there is no substrate nutrient left or the substrate is overly compressed; all these can lead to plant deficiency. To identify if the substrate is the cause of nutrient deprivation in the aquarium plant, you will see gas bubbles are emerging from the bottom if you look closely. The plants are poorly rooted and stunted or rotting.


  • Breakup the substrate, so it loosens up
  • Change the aquarium substrate to better material and add laterite to it

б) Inadequate Water Temperature

When the water temperature is icy-cold, the aquarium plants would hibernate or begin to die off gradually. When the water temperature is hot, the plant stems will not grow adequately; the leaves would be scanty. Irregular water temperature can be a result of a malfunctioning heater or low voltage heater.

You should consider replacing the heater so you can meet your water temperature needs. However, monitor the temperature often in case the aquarium is broken.


  • Aquarium plant deficiency happens in plants when the environment is not conducive
  • Potassium deficiency causes pin-like holes on the leaves of aquarium plants
  • Manganese, magnesium and iron causes the leaves to turn yellow or brown
  • Nitrogen deficiency causes yellow and white or translucent leaves in aquarium plants
  • Oxygen deficiency delays aquarium plant growth and excess algae growth in the tank
  • Carbon dioxide inhibits photosynthesis which in turn reduces the oxygen in the water content

You can avoid aquatic plant deficiencies by testing the different nutrient levels often. Be observant so you can tackle whatever problem that arises easily and quickly.

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