Can Aquarium Plants Kill Fish: Busting Myths and Clearing Facts

Live plants are added to aquariums for known benefits. There is a list of advantages your fish and tank setup enjoy when there are aquarium plants. However, when these plants are not taken care of, they may harm the fish in ways you would have never thought.

So, the quick answer to the question, ‘Can live aquarium plants kill fish?’ is yes, but only under certain circumstances. This article is going to be very beneficial for aquarists, especially beginners who are in a dilemma about adding live aquarium plants to their tanks. Here, you will understand in what cases aquarium plants can harm the fish and disturb the tank’s environment. It will help you avoid those circumstances and keep your fish safe and healthy.

Keep reading!

When do aquarium plants harm fish?

Usually, they won’t! In fact, live aquarium plants provide a healthy environment to the fish where they feel more connected to the nature. From mimicking the natural habitat of fish to filtering the tank’s water and improving its aesthetic, there are plenty of benefits that aquarium plants offer.

Yet, there can be certain downsides that arise in specific conditions that may disturb the tank’s environment. Below, we have listed them-

Plant Rot

When you are introducing aquarium plants in the tank, you can’t just add and forget about them. They need proper care and an inspecting eye. If by any chance, the plants start to rot, they would hamper the entire tank’s water and pose health issue to fish.

Aquarium plants rot when they are not exposed to proper light and nutrition. As a result, they start wilting and eventually rot. As the rotten plants keep accumulating, they release ammonia that turns into nitrite– one of the toxic gases for the tank’s environment. It is when they can harm the fish and other aquariums habitants.

Even though there could be many reasons for ammonia build up such as fish excreta and uneaten food particles but when there are healthy live aquarium plants, they absorb and neutralizes its affect. This way, they keep the tank’s water suitable for the fish’s survival. However, when the only thing neutralizing ammonia it decays and rot, the aftereffects could be hazardous.

When you are adding fish to the tank, there is a high need to keep the level of harmful gases low and consistent. It is one of the ways to ensure their health. Therefore, adding live plants and keeping good care of them is essential.

How to prevent plant rot in an aquarium?

• Add only those aquarium plants that are suitable for your tank’s environment.
• Maintain proper water parameters such as pH, temperature, and hardness to ensure plants’ health.
• Make sure the plants are getting the amount of light they require for photosynthesis, as too much and too low light levels hamper growth.
• Remove the decaying parts of the plant by trimming and getting rid of the dead plant materials immediately to prevent ammonia development.
• Avoid overcrowding the tank either with fish or with the aquarium plants.
• Keep an eye out for the pests.

When you are taking good care of your aquarium plants and ensuring their health, fish are less likely to suffer due to toxic gases.

2. Suitable plants

Not every plant is suitable for your tank and this is what every beginner must understand. Even though there are plenty of aquarium plants, but a plant put in wrong environment eventually rot and die. Therefore, you need to be 100% sure that the plant is suitable for your tank’s conditions before adding.

Most of the fish munch on aquarium plants’ leaves. If you have added such fish along with plants whose leaves are not good for fish health, it will pose danger. It is when having a complete knowledge about the eating habits of fish and if the leaves of the aquarium plants are safe for munching becomes essential.

Besides this, another factor that plays a major role in how the plant grows is While some aquarium plants grow in emersed conditions, others grow well when kept submerged. In ’emersed’ condition, the roots of the plants are inside water while the rest of the plant grows above the water surface. On the other hand, in ‘submersed’ conditions, the entire plant is dipped inside the water, where it grows perfectly, relying on the water environment for nutrients.

Growing aquarium plants in condition opposite to what they prefer will eventually rot them. As the rotten material keep accumulating, ammonia and other toxic gases will produce, harming fish health and tank’s ambiance.

Therefore, a careful selection of aquarium plants is the foremost step towards a healthy tank environment which ensure healthy fish.

How do you know the aquarium plant is rotting?

The aquarium plants start showing signs of decay before they fall off. Therefore, inspecting the plants daily and keeping an eye on them will help you understand if their health is compromised.

Below are a few telltale signs that indicate that your aquarium plant is rotting-

• Discoloring leaves– If the leaves seem turning yellow, brown, or black, it could be a sign that the plant is suffering due to some reason and being unhealthy. Some leaves will discolor and drop off as a part of their natural cycle, but when the young leaves are not vibrant green and are fading colors, you need to be careful and look for the issues.
• Wilting leaves– Leaves wilt, and stems appear limp and droopy only when the plant is rotting. So, you need to check for the symptoms before the entire plant decays and rot.
• Mushy leaves– While the leaves of healthy aquarium plants will be firm, those rotting will turn mushy or too soft to touch.
• Odor– Decaying plants smell bad. If you experience a foul smell from the plant, it indicated that there is some problem and the plant is rotting.

In addition, some plants will show visible signs of rotting such as black and brown spots on the leaves and stem. If you notice any such sign in your plant, there is high time to either remove it from the tank or wait and watch for a day or two for it recover by creating healthy ambiance in the tank.

Often, the plants appear decaying and dying but sometimes they are just shedding off their older parts. Once done, new leaves and stems emerge. Therefore, instead of immediately removing the entire plant from the tank, look for the other parts as well and check if they are healthy or decaying. You can also make a few changes to your water parameters to prevent further issues.

It is when the role of regular monitoring and maintenance comes into play.

3. Overcrowding and overgrowth

In the quest to make the tank look aesthetic and livelier and mimic the natural environment, aquarists end up overcrowding the tank with plants. Besides overplanting, allowing the plants to overgrow is also one of the problems that lead to serious repercussions.

Even though adding aquarium plants help to filter the water and oxygenate the tank, too much will only pose problems which may cause fish death.

The major reason behind it is the high demand of biological oxygen. Every creature in the tank require oxygen– be it the fish, shrimps, snails or even the good bacteria. In addition, when the plants are in resting phase, they need oxygen for respiration.

We all know that plants generate oxygen and absorb carbon dioxide in the presence of light. But, when they come to their resting phase, that is, during night or when there is no light, they take oxygen to respire and release carbon dioxide to break down sugar for energy. It is when the need of oxygen in the tank increases.

So, as the night approaches, the demand of oxygen rises and it is when the plants are not producing but consuming it. As a result of this high biological demand of oxygen, the fish may feel suffocated and show signs of stress. When the fish don’t get enough oxygen throughout the night, they may die.

Managing overcrowding and overgrowth of aquarium plants

Irrespective of the fact that live aquarium plants are essential for the tank, it is important to check their growth. Overgrowing fauna compete for oxygen just like other aquarium habitats. Plants will predominantly absorb all the oxygen, leaving little for the fish.

Therefore, you need to trim the overgrowing plants after regular intervals. Also, maintaining a moderate amount of fauna will ensure that everyone gets enough oxygen to survive. When you have a lesser number of plants or what’s suitable for the tank, you will spend less time maintaining them. There will be less debris, and the tank will be easy to clean and maintain.

Conclusion

Aquarium plants only create a healthy environment in the tank. However, if you don’t know what happens when you overcrowd the tank with plants or allow them to overgrow, things may turn upside down. Likewise, letting the debris accumulate in the tank and not cleaning the substrate or changing the water will again hamper the fish’s health.

So, if you think that you can keep adding as many aquarium plants in the tank as you want and nothing bad will happen, you could be wrong. If you decide to give a forest look to your tank by adding a lot of aquarium plants, you need to maintain it daily. From trimming the overgrowth to removing the debris every day, it should become your routine. If you can dedicate fully to your tank, there will be no harm in adding too many plants. The other way around to ensure safe and healthy environment is to keep the number of plants limited to make the tank manageable.