Fish Tank Plants To Avoid – Plants That Hurt Fish Or Die In Aquariums


By: Tonya Barnett, (Author of FRESHCUTKY)

For beginners and aquarium enthusiasts alike, the process offilling a new tank can be exciting. From choosing fish to selecting the plants that will be incorporated into the aquascape, the creation of ideal aquatic environments requirescareful planning and attention to detail. Unfortunately, things may not alwaysgo according to plan. This is especially true when incorporating submersed liveplants. Here we will learn about fish tank plants to avoid.

What Shouldn’t You Put in a Fish Tank?

Buying aquatic plants for the aquarium can add a uniquedesign to tanks. Not only can live aquatic plants provide natural habitat forfish, but may also improve the overall water quality of your tank. While brightand vibrant foliage is appealing and adds visual interest, owners mayfrequently find that these are plants that die in aquariums.

When purchasing plants for the aquarium, it is important tothoroughly research each type to be used. Not only will this provide valuableinsight into whether or not these are plants that hurt fish, but will alsoallow greater information in regards to the specific needs of the plant.

Unfortunately, misinformation is very common when purchasingaquatic plants online and in retail stores.

If you have purchased plants that die in aquariums, it islikely that the plant species was not appropriate for the aquatic environment.Many plants that have been produced by large scale greenhouses are bettersuited for growth in terrariums or demonstrate an emerged growth requirement.Emerged plants will not grow in aquatic conditions, though portions of theirgrowing season may be spent in water. Complete submersion in the fish tank willonly lead to the ultimate decline of these plantings.

Included in plants not to put in an aquarium are those thatare obviously non-aquatic varieties. When submerged, these plant types willdisintegrate and die rather quickly. Some ill-suited plants which are commonlysold for aquariums include:

  • Crimson ivy
  • Caladium
  • various species of Dracaena
  • plants with variegated foliage

By choosing aquatic plants, and with proper regulation ofnutrients and atmosphere within the tank, aquarium owners can create a thrivingecosystem of beautiful submerged plants and fish.

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Pothos Plant in Aquariums – 5 Benefits & Growing Tips

Disclosure: I may earn a commission when you purchase through my affiliate links. As an Amazon Associate I earn from qualifying purchases. – read more

Pothos is an easy to grow houseplant, which can thrive in a wide range of conditions. Pothos plants are also good air purifiers, because they can remove harmful chemicals from indoor air.

Pothos plants can be grown in both soil and water. For this reason, many aquariusts decorate their aquariums and terrariums with pothos plants.


Planning a Planted Aquarium

Planted tanks are a popular and rapidly growing segment of the aquarium hobby, one that allows hobbyists to combine the beauty of nature with the benefits of a balanced ecosystem. Unlike a traditional aquarium, live plants are the primary focus, with fish being an accent or compliment to the overall effect.

Benefits of Live Plants in an Aquarium:

  • They enhance water quality and help prevent algae growth by using nutrients produced by fish waste, uneaten food and organic debris.
  • They produce oxygen during daylight hours, which is used by fish and helps stabilize pH. Fish, in turn, release CO₂, which plants use as a food source.
  • Fish tend to feel safe which encourages them to stay out in the open and develop more vivid colors.
  • Plants encourage many types of fish to spawn and give newly-hatched fry a place to hide while they grow.

Planning a Planted Aquarium:

Planted tanks are less work to maintain than conventional aquariums, but they require proper planning. Special attention should be paid to tank dimensions, lighting, substrate, fertilizers and choice of plant and fish species. A well-planned and maintained planted aquarium will provide years of enjoyment and relaxation. Let’s get started!

Selecting an Aquarium for Live Plants

Consider the types of plants – and fish – you want to keep and then choose an aquarium that best suits their needs. Almost any sized aquarium can be used to set up a planted tank, however taller tanks require stronger lighting for certain plant species. Aqueon offers a wide range of aquarium sizes suitable for planted displays.

Planted Aquarium Lighting

The key to success with aquatic plants is using the correct light intensity and spectrum. The spectral output should be between 6500 and 8000 Kelvin. Intensity depends on plant species and water depth. Aqueon OptiBright® MAX and OptiBright®+ LED lights offer the desired spectrum for aquatic plants, along with dimming capabilities and automatic sunrise/sunset to mimic a natural day/night cycle. Aqueon’s Clip-On Planted Aquarium LED light is designed for small aquariums up to 20 gallons.

The term “watts per gallon” is often used for choosing the best light for a planted aquarium. Watts describe how much electricity a light uses, not how much light energy it produces. While not entirely accurate, it is a useable formula with standard fluorescent lights. With the introduction of HO T5 and LED lighting, this comparison no longer works across different lighting platforms. PAR (photosynthetically active radiation) is a better way of rating aquarium lighting for plants.

Aquatic plants can be divided into low, medium and intense light-requiring groups. If you’re adding plants to an existing aquarium, ask your local aquatic store expert to recommend plants that are compatible with the light you have. The alternative is to choose the plants you want to grow and purchase a light that meets their needs. Be sure to exchange standard fluorescent and HO T5 bulbs with aquarium plant-specific bulbs and replace the bulbs every 10 to 12 months.

Substrate for a Planted Aquarium

Choosing the proper substrate is essential for success with rooted plants. Coarse sand or fine gravels work best. Avoid pebbles or large, chunky gravel (a little here and there is OK for accent, but not as the main substrate). Several plant-specific substrates are available that are infused with iron and other minerals to promote healthy plant growth. Some have the added benefit of buffering pH and softening water, both of which are desirable for many plant species. You can also use standard aquarium sand or fine gravel and add plant nutrient tablets where needed, or layer/mix it with plant-specific substrates. Do not use coral or dolomite substrates, as they slowly dissolve and may raise pH and alkalinity above desirable levels.

Planted Aquarium Water Chemistry

Water chemistry is important to plants. In general, they do best in moderately soft water at a pH between 6.8 and 7.8. If your tap water is exceptionally hard or has a high pH, consider using reverse osmosis or deionized water with trace minerals and buffers added.

Nutrients and Fertilizers for a Planted Aquarium

Aquatic plants use iron, magnesium and potassium as well as other macro and micro-nutrients to grow and develop their best colors. Some plants feed primarily through their leaves, while others are root-feeders. Some plants do both. Use an enriched plant substrate when setting up your aquarium for root feeders or insert fertilizer tablets around the roots on a regular basis. Dose liquid fertilizers such as Aqueon Plant Food weekly for leaf-feeders. Do not use liquid fertilizers that contain copper if you keep decorative snails or dwarf shrimp, as copper can be harmful to them.

Planted Aquariums and CO2

In addition to minerals and fertilizers, plants also use carbon to grow. The use of CO2 can be a significant commitment, but its effect on plant growth and color is dramatic and well worth the effort. Automated systems are the easiest to use, but more affordable DIY systems are not difficult to build. Liquid carbon supplements are also available. When adding CO2 or liquid carbon, it may be necessary to increase liquid and tablet nutrient dosing to keep up with more rapid plant growth.

Live Plant Selection For a Planted Aquarium

A planted aquarium is living art, and designing the layout requires careful thought and planning. Draw a rough sketch of the plant and hardscape – rocks and driftwood – layout. Once you’ve installed the hardscape, start in back with tall plants such as Vallisneria or Sagittaria grasses, or stem plants that grow rapidly. Use showy species like Amazon Swords, large Anubias or tiger lilies in the middle and low-profile plants like short Cryptocorynes, dwarf Anubias, mosses or baby tears in the foreground. Leave enough space around large broadleaf species to prevent them from blocking light to smaller plants as they grow.

Fish Selection for Planted Aquarium

As mentioned, fish are an accent in a planted aquarium, not the main feature. Choose species that complement the overall feel and character of the tank. In smaller aquariums, schooling fish like tetras or rasboras are good choices, along with rams and Apistogramma dwarf cichlids. For medium to larger sized aquariums, consider Congo Tetras, Kribensis or a collection of Rainbowfishes. Discus and Angelfish make excellent choices for aquariums of 100 gallons or more. Bottom cleaners can include Corydoras catfish, Otocinclus and certain species of loaches. Avoid herbivorous fish like Tinfoil Barbs, Silver Dollars, and plecostomus as they will eat your plants!

Finding Balance in a Planted Aquarium

When you first set up an aquarium there is no biological balance. This takes weeks, if not months to achieve, and in the meantime, things may not go perfectly. Planted aquariums are no different and, in fact, can be further complicated by using fertilizers, CO2 and strong lighting. Strong light produces rapid plant growth, which in turn, puts an increased demand on fertilizers and CO2. Adding too much fertilizer can cause algae blooms, and too much CO2 can cause fluctuations in pH.

The best approach is to start slowly, add nutrients in small amounts and be patient. If you make changes, make them minor and allow at least 2 weeks to evaluate the effects. Be consistent, put your lights on a timer, dose nutrients faithfully and don’t make sudden drastic changes to the system. Take notes and keep a log of any changes in dosing, daylight hours, etc. Eventually your planted aquarium will find balance and go on auto-pilot.

Setting up a planted aquarium is a wonderful way to bring a piece of nature into your home or workplace. With good planning and consistent maintenance, the benefits can last a lifetime!


Why would you ever salt a freshwater aquarium?

This is the 64-million-dollar question.
Those who argue for salting say that keeping your freshwater tank lightly salted can improve the health of your fish, act as a preventative agent against various kinds of parasitic infections, and help to cure various diseases.

Adding salt is said to make life easier for your fish, by helping to keep them stress-free, reducing osmotic pressure in the water, inhibiting the uptake of toxic nitrates, supporting the production of their protective slime coat and helping to heal wounds more quickly.

Those are some pretty big claims. Is there any scientific reasoning behind them or are they old (fish) wives’ tales? Let’s take a closer look at some of the key issues.

Osmotic regulation, or osmoregulation

Osmoregulation is one of the most common arguments that comes up in relation to adding salt to your freshwater aquarium.

Salt does have a direct relationship to the water pressure in your aquarium.
If you remember your high school science lessons, you probably learned about osmosis – where salts and fluids can move through a semi-permeable membrane from a strong concentration to a weaker one.

This is nature’s way of trying to balance the concentration of salts and electrolytes in the water.
Your freshwater fish are naturally more salty than the water that they live in, and their skin is semi-permeable.
This means that by the process of osmoregulation, fish constantly discharge body salts into their tank water, and take tank water into their bodies.

This is osmosis at work, where your aquarium water is trying to equalise the salinity of your fish with the salinity of your aquarium.
To balance the process of osmosis, your fish need to reabsorb salt from their tank as they release a vast amounts through urination. Some freshwater fish can produce their own body weight in urine in just three or four days.

This process is constant and the salinity level in the tank changes constantly, though usually at the micro-level as the quantities are so small relative to the overall volume of your tank.
However, if your fish don’t absorb enough electrolytes from the water – for example, if they’re under stress – they can go into what’s known as osmotic shock.
Osmotic stress can be a common side-effect of transport, for example, when you’re bringing fish home from the pet shop.

Proponents of salting your aquarium claim that by gently boosting the salt levels in your tank when your fish are stressed, you can make their life easier as their cells don’t need to work so hard via the osmotic process.


Half-terrarium, half-aquarium, a paludarium has water and dry land areas for plants to grow. Stock a paludarium with bromeliads, jewel orchids, Phalaenopsis orchids, mosses, African violets, creeping fig and philodendron. Reptiles and amphibians do well in paludariums, since many require dry and wet areas. Small fish such as cherry barbs, platies and rasboras do well in paludariums. Avoid fish species that eat plants, such as cichlids.

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Watch the video: Common Fish Diseases: How to Prevent and Cure Illness in Aquariums


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