Nutrient Deficiencies: why your Aquarium Plants Are Dying

Nutrient Deficiencies: Why Your Aquarium Plants Are Dying Are your plants still dying despite having the best planted aquarium setup? This could be due to a deficiency of nutrients. Even if your plants are receiving …


Nutrient Deficiencies: Why Your Aquarium Plants Are Dying

Are your plants still dying despite having the best planted aquarium setup? This could be due to a deficiency of nutrients. Even if your plants are receiving regular fertilizers, they might be missing essential building blocks that hinder their growth and thrive. We will show you how to identify the signs of nutritional deficiencies and help you take preventative measures to ensure your plants don’t die.

Illustration of a healthy, normal-looking leaf

Types of Nutrient Deficiencies in Plants

Nitrogen Deficiency

Low nitrates can be a problem in planted tanks, especially for beginners who are taught to perform routine water changes each week without testing for actual nitrate levels. This habit, while fine for fish only tanks, can lead to a lack of nitrogen, even if you are regularly dosing fertilizers. Old leaves that turn yellow or translucent are classic signs of a nitrogen deficiency. This happens because the plant uses nutrients from its bottom leaves to make new ones.

Signs that old leaves may have a nitrogen deficiency

A second reason you might run into nitrogen deficiency could be that you are following the recommended fertilizer dose instructions but the plants grow to three times the size of their original size four months later. You still need to apply the same amount. Just as you automatically feed more food if you add more fish to an aquarium or if they grow bigger over time, you need to feed your plants more as they get taller or propagate.

If you are pruning or removing a lot of plants, the same principle applies. Make sure to reduce the nitrogen. Our recommendation is to try and match the amount of fertilizer you use (whether it’s liquid fertilizers for plants that feed from the water column or root tabs for plants that feed from their roots) with your plants’ growth.

Now, if you see yellow or translucent leaves on a brand-new plant that was recently added to your aquarium, this may be a sign of melting, not nitrogen deficiency. Most plants that you buy online or locally were raised in water. Emersed (or out of water) leaves can melt and make room for submerged-grown or underwater-grown leaves. This melting effect can occur even if the plant is purchased from another hobbyist.

Stem plants that have lost their lower leaves due to melting tends to become bare, with no leaves above. You can trim the healthy-looking top off your stem plant once it is fully grown to submerged-grown foliage. Then, replant the stem so you don’t see any skinny stems. Amazon swords, cryptocoryne plants, and stem plants are notorious for melting in new environments, whereas anubias and java fern are pretty hardy in comparison.

Iron Deficiency

Plants that lack iron display yellowing or paleness on their newest leaves with leaf veins that remain darker in color. Older leaves look more normal.

Signs of iron deficiency on new leaves

It can be difficult for iron to be incorporated in common fertilizers. So instead of buying more fertilizer that is all-in-one, consider purchasing an iron-specific product to treat your plants. To enhance the color of red-colored plants, you can add extra iron.


Potassium Deficiency

This condition is easy to diagnose because the plant’s leaves will develop distinctive pinholes that are sometimes rimmed with brown or yellow. Certain plants like java fern and anubias thrive in environments with more potassium, so watch out for those signs. You can buy a potassium-specific supplement, but we already fortify Easy Green with extra potassium to address such problems. Therefore, treatment can be a simple matter of just dosing more of our broad-spectrum fertilizer.

Signs of potassium deficiency in old leaves

Phosphate Deficiency

Plants also consume phosphate in large amounts. The older leaves will be most affected. They will turn yellow and develop soggy brown spots. As the leaves begin to die, green spots may form. This condition is more uncommon, since fish foods like flakes contain phosphates. Sometimes, however, people will use phosphate absorb pads in their filters to stop algae growth. This causes the plants to become starved.

Signs a phosphate deficiency in old leaves

Magnesium Deficiency

A lack of magnesium is similar to an iron deficiency. In this instance, older leaves are affected. Sometimes, the edges of leaves may become droopy. Magnesium is typically included in most general-purpose fertilizers, so dose more of it as part of your fertilization routine or consider using a magnesium supplement or Epsom salts to supply this nutrient. This condition can often be linked to calcium deficiency.

Signs of magnesium deficiency on old leaves

Calcium Deficiency

If you see new leaves growing in a twisted, gnarled fashion, this is usually related to a calcium or water hardness issue. Low water hardness is often a sign of calcium, magnesium, or manganese deficiency. You may need to supplement your water with special salts if you have soft water, RO/DI (reverse-osmosis deionized), or crystal shrimp. You can also slowly increase calcium levels and hardness by adding crushed coral to the substrate or filter, Wonder Shell to the aquarium, or Seachem Equilibrium minerals.

Signs that new leaves may have calcium deficiencies

How to fix nutrient deficiencies

In order to properly treat your plants, identify the nutrient deficiency and how you’re going to fix it (e.g., add more fertilizer or specific supplements, increase the water hardness, feed more fish food, and/or remove some plants). Make sure you are getting the right nutrients if you decide to add more fertilizer. Easy Green does not affect water hardness, calcium, or other levels.

You can solve most deficiencies by increasing your intake of all-in one fertilizers. For instance, if you are missing nitrogen, it is likely that you are also missing other nutrients. Your plants will soon run out of nutrients if you only give them a nitrogen supplement. Dosing Easy Green Tabs or Easy Root Tabs gives your plants more of the micronutrients and macronutrients they need (in the right amounts).

If you only get one fertilizer for your aquarium plants, we recommend Easy Green. It was originally designed for our store because it is simple to use, doesn’t require you to measure any additional nutrients, and is reasonably priced. Easy Green is a liquid fertilizer that contains all the nutrients your aquatic plants require to thrive. Unlike other ammonia-based fertilizers, Easy Green is completely safe to use with fish, shrimp, snails, and other invertebrates.

It takes about two to three weeks to notice a difference in the plants. Then you can assess if your actions made a difference. Based on these results, adjust your fertilization schedule so that it matches what the plants actually eat. Planted aquariums are an ever-evolving landscape with fertilizer needs that must change as plants grow over time, leaves are pruned, and plants are added or removed. You’ll have a beautiful and thriving aquarium if you take the time to inspect your plants and identify any nutritional deficiencies.

For a quick reference guide, get our free infographic to plant nutrient deficiencies here: