Encyclopedia of aquarium plants

Peter Hiscock

ENCYCLOPEDIA OF

AQUARIUM PLANTS

DE VECCHI EDICIONES

The arching crinkled leaves of Aponogeton boivinianus dominate this aquarium display and provide sanctuary for the shoaling fish.

The author or publisher cannot be held responsible for the information (formulas, recipes, techniques, etc.) contained in the text, even though the utmost care has been taken in the writing of this work. In the case of specific - often unique - problems of each particular reader, it is advisable to consult aqualified person to obtain the most complete, accurate and up-to-date information possible. EDITORIAL DE VECCHI, S. A. U.

© Editorial De Vecchi, S. A. 2024

© [2024] Confidential Concepts International Ltd., Ireland

Subsidiary company of Confidential Concepts Inc, USA

ISBN: 978-1-63919-818-4

The current Penal Code provides: "Anyone who, for profit and to the detriment of a third party, reproduces, plagiarizes, distributes or publicly communicates, in whole or in part, a literary, artistic or scientific work, or its transformation, interpretation or artistic performance fixed in any medium or communicated by any means, without the authorization of the holders of the corresponding intellectual property rights or their assigns, shall be liable to imprisonment for a term of six months to two years or a fine of six to twenty-four months. The same penalty shall be imposed on anyone who intentionally imports, exports or stores copies of such works or productions or performances without the said authorization.

Echinodorus uruguayensis, one of many echinodorus species and cultivars available for aquarium use. They provide bold shapes and contribute an elegant style to planting displays.

Contents

PART ONE: PRACTICAL SECTION

Comprehensive practical guidance on all aspects of creating a stunning planted aquarium, from how plants work to the value and techniques of regular maintenance. The topics of water quality and filtration, choosing substrates, and correct planting methods are all featured in detail. Lighting, feeding and propagation are also key areas to receive attention, followed by a major section on aquascaping.

PART ONE PRACTICAL SECTION

The natural biology of plants

Water quality and filtration

The right substrate

Choosing and planting

Lighting the aquarium

Feeding aquarium plants

Propagating aquarium plants

Maintaining a planted aquarium

Aquascaping

Fish for the planted aquarium

PART TWO: PLANT PROFILES

A wide-ranging survey of more than 150 popular aquarium plants presented in A-Z order of scientific name, including a brief review of non-aquatic plants suitable for temporary display in the aquarium. The majority of the featured plants are shown in colour photographs, many with accompanying detailed views. Full botanical, practical and growing information is provided for each plant, including common name, origin, height, growth rate, suitable aquarium zone, lighting requirements, optimum temperature range, propagation techniques and difficulty rating.

PART TWO PLANT PROFILES

Anubias species

Aponogeton species

Cryptocoryne species

Echinodorus species

Hygrophila species

Tropical lilies

Non-aquatic plants

PART ONE

PRACTICAL SECTION

Over the past 30 years or so the aquarium industry has boomed, and it is now easier than ever for aquarists to obtain the equipment, treatments and fish and plant species they require to create a stunning aquarium. Experienced, long-term hobbyists will often tell of the difficulties they encountered when trying to obtain species and maintain aquariums in ‘the old days’. Much of our success today is due to these pioneering enthusiasts, who were forced to experiment with various aspects of plant and fish care to find the best methods of maintaining planted aquariums. The knowledge they passed on and the methods they devised for aquarium maintenance and keeping plants healthy are now standard practice.

For beginners and newcomers to keeping aquarium plants, there is an increasing amount of information available relating to plant care, and at first glance, it can appear quite daunting. It is not uncommon to find conflicting advice from different sources regarding methods of cultivation or solutions to problems. However, a basic understanding of the requirements of aquatic plants and how to care for them is essential for you to set up and maintain a successful display. Thankfully, a complete understanding of all the aquatic processes that govern good plant care is not required from the start. It is possible, and probably more useful, to learn as you go along.

The first part of this book focuses on practical matters, beginning with the biological processes that occur within plants and the systems they use to thrive in the aquatic environment. Understanding how plants work and why certain conditions are required for healthy growth are vitally important topics. If you acquire a basic understanding of the biology of plants and their requirements, the rest will follow.

Water quality dictates much of the aquarium environment, and in the water quality and filtration section, the properties of water are examined, along with the processes that occur in the aquarium that alter water quality. Filtration and the types of filter suited to a planted aquarium are also discussed.

The successful health of plants depends largely on the environment they are kept in, and preparing this begins well before any plants are introduced. For example, the substrate provides much more than a simple rooting medium for plants. A whole chapter in this part of the book is dedicated to the choice of substrates, the vital role they play and how to prepare, install and care for them properly.

Other sections in this part of the book focus on choosing aquatic plants and preparing them for planting, lighting the aquarium and feeding plants. In the feeding chapter, all the nutrients required by plants are examined in detail, including the role they play in plant health and growth. Fertilisation methods are explained and applied to aquarium situations.

Once planted, you must keep your aquarium display looking its best, so ongoing care and maintenance are discussed next, as well as the correct methods of dealing with pests such as algae and snails.

In the penultimate chapter of Part One, we embark on the exciting prospect of aquascaping – how to design a superb aquarium display, using not only plants, grouped for maximum effect, but rocks, wood, bark and other decor. And if you need further inspiration, take a look at the individual aquascaped display tanks that reflect different environmental conditions and a range of natural biotopes. We end with a brief look at some of the fish that will complete the display. Above all, this part of the book forms a vital resource of practical guidance that you can refer to at every stage of setting up and maintaining your aquarium. With a little time and patience, a stunning display aquarium is not difficult to achieve. You will find the result and rewards are well worth the effort involved.

Azolla caroliniana

Microsorium pteropus ‘Tropica’

Planting ludwigia

Trimming plants in the aquarium

The natural biology of plants

Although there are a few exceptions, plants in general do not consume other organisms to obtain the energy and the basic elements they need to live, grow and reproduce. Instead, they use the processes of photosynthesis to obtain energy, and absorb vital elements directly from the surrounding environment. This simplified way of life has allowed plants to thrive and spread in many habitats, becoming the basis of support for more complex organisms and food chains. Plants are producers rather than consumers; they ‘produce’ biological material rather than ‘consume’ it. Plants themselves are eaten by herbivorous animals, which in turn are consumed by predatory animals. Clearly, plants have an important place in the natural world as a provider of food sources; without them, the diverse range of animals would not survive.

Plants developed on land before venturing under water and although aquatic plants are highly adapted to the underwater environment, many of their physical attributes can be traced back to their terrestrial ancestry. Other attributes have been lost in the course of evolution; fine hairs used to trap moisture and stiff, strong stems to support leaves are not needed underwater. Conversely, aquatic plants have developed certain less noticeable attributes to aid underwater survival. Many of these are based on the production of chemicals that ‘condition’ the substrate so that plants can take up nutrients, and chemicals used to protect against consumption by animals and competition from other plants. Physical changes can also be seen in the development of complex leaf structures designed to maximise the amount of light received by the plant, allowing it to survive in harsh conditions underwater.

Looking at the biology and structure of aquatic plants, helps us to understand why certain conditions are needed in the aquarium if we want to keep aquatic plants successfully. A greater understanding of the functions of aquatic plants will also help to identify the causes and solutions to problems encountered when keeping plants in the aquarium.

Oxygen produced during photosynthesis can be clearly seen on this Echinodorus sp. leaf. The oxygen is a waste product and is released back into the water and used by other organisms.

Without the plants and other vegetation found in and around this river, there would be very little life beneath the surface. Plants provide the basis for most complex ecosystems.

Photosynthesis

The unique function that plants possess is the ability to obtain energy from sunlight, carbon dioxide and water, using the process of photosynthesis. Photosynthetic cells within the leaves and stem tissues contain pigments that trap light energy to break down the molecular structure of water (H2O) into hydrogen and oxygen. The hydrogen binds first to carbon dioxide and then oxygen to form glucose, which is a basic sugar and an important source of energy. Some oxygen is left over from this process and is released back into the water, where it is either used up by bacteria and animals or released into the atmosphere at the water surface.

The glucose produced from photosynthesis is water soluble and, if stored in large quantities, will absorb water and enlarge the cells that contain it. Obviously, this is undesirable for plants, so the glucose is quickly converted into an insoluble starch compound and transported to various parts of the plant for storage, in most cases to the upper root area. Some plants can house vast amounts of starch in specially designed root structures. One of the most distinctive examples is the banana plant (Nymphoides aquatica), which produces numerous ‘banana-shaped’ roots that store starch and other nutrients. Many plants store starch in tubers, rhizomes and bulbs. The starch can be easily converted back into glucose and transported around the plant when needed.

HOW PHOTOSYNTHESIS WORKS

1. Pigments such as chlorophyll trap sunlight energy and use it to ‘power’ photosynthesis; 2. The carbon, oxygen and hydrogen of carbon dioxide and water are ‘rearranged’ within the plant cells.

A) Carbon dioxide supplies the carbon to build carbohydrates; B) Water is easily absorbed by aquatic plants; C) Glucose produced from photosynthesis is stored and used as a food source; D) Oxygen is released as a waste product.

Factors affecting photosynthesis

A plant has little control over the rate of photosynthesis that occurs within its cells. A number of environmental factors are responsible for the productivity of the photosynthetic cells and it is always the factor in least supply that limits the rate of photosynthesis. The aim in the aquarium is to remove the majority of constraints on photosynthesis to obtain the optimum level. Higher rates of photosynthesis will encourage faster growth, reproduction and improved plant health. Light is the most obvious environmental factor, but temperature, carbon dioxide levels and nutrient availability also affect the rate of photosynthesis.

LIMITING FACTORS ON PHOTOSYNTHESIS

A) Assuming that the nutrient supply and other environmental conditions are correct, three factors affect the rate of photosynthesis: temperature, carbon dioxide (CO2) and light; B) If one factor is in short supply, photosynthesis will be restricted. Increasing the temperature and CO2 content will not increase photosynthesis if the plants do not receive enough light; C) In most aquariums, the CO2 content of the water is the limiting factor. Even with the correct temperature and good lighting, plants will not grow well if they receive little CO2; D) Once CO2 and lighting levels are sufficiently high, and the temperature is at an optimum level, the rate of photosynthesis will increase rapidly. Mostly, this will produce a healthier plant.

Light

Plants will only photosynthesise when suitable light is available to be trapped by the photosynthetic cells. At night, plants stop photosynthesising and only start again in daylight. The intensity and duration of light are the factors that affect the rate of photosynthesis. In nature, most tropical plants experience about 12 hours of sunlight in a 24-hour period. The intensity of light varies throughout the day. Depending on the location of the plant and the shading, it is strongest in open areas around mid-day. In the aquarium, the same duration should be employed and in most cases, a bright light source is preferable. If the light is left on for a longer period, the photosynthetic period will also increase. This may bring its own problems; it is possible that plants will over-synthesise and become damaged by literally wearing themselves out.

Providing other factors are available in the right supply, the rate of photosynthesis is directly proportional to the intensity of light received by the plant until a light saturation point is reached. Slow-growing plants, which often grow in shaded areas in nature, may experience problems in strong light conditions. These plants will assimilate nutrients and carbon dioxide at a slower rate, so an increase in photosynthesis spurred on by bright light may cause nutrient deficiencies within the plant, even when large amounts of nutrients are available in the surrounding environment.

These tropical lilies (Nymphaea sp.) produce leaves above the surface to obtain carbon dioxide and sunlight with ease. They also provide cover for other aquatic creatures.

Temperature

Heat affects all the biological processes within an organism and, providing the change in temperature is within the tolerance of the organism, an increase in temperature generally causes an increase in metabolism. In plants, an increase of 10°C (18°F) will roughly double the rate of photosynthesis, assuming all other factors are favourable. However, if the surrounding environment becomes too warm, the plant will simply begin to die, and photosynthesis will stop. An increase in temperature affects not just photosynthesis, but the whole metabolism of a plant, so it also increases the plant’s requirements for nutrients, carbon dioxide and other elements. For this reason, simply increasing the temperature of an aquarium to aid plant photosynthesis and, therefore, plant growth, is unlikely to work. If the aquarium is set at a temperature based on the natural environment of the plants, then a lack of growth, or a need to increase growth rates, can be better explained or achieved by looking at the other limiting factors.

Carbon dioxide

Plants take up carbon dioxide from the surrounding water and substrate. If carbon dioxide is not available in sufficient quantities, many plants have developed ways of obtaining carbon-containing compounds and creating their own source of carbon dioxide. This occurs more in hardwater plants, including Vallisneria and Egeria species, which experience lower carbon dioxide levels in nature. In hard water, carbon dioxide is more likely to bind to minerals, creating carbonates. Many plants will take up these carbonates and break them down, allowing the carbon to become carbon dioxide.

Plants that regularly produce leaves above the surface have developed methods of utilising carbon dioxide gas from atmospheric air, where the concentrations are much higher. Floating plants have constant access to the air, so it is far easier for them to obtain carbon dioxide from the surrounding air through the leaves, in the same way as terrestrial plants. Some stem plants also produce aerial leaves or stems above the surface. Air drawn down the centre of the stem is used both to obtain carbon dioxide and to oxygenate root areas.

In most natural situations, it is a lack of sufficient carbon dioxide that limits photosynthesis and prevents strong growth in aquatic plants. In the aquarium, the aquarist has more control over carbon dioxide levels and can achieve a constant high level by using carbon dioxide fertiliser systems.

This Saururus cernuus plant is sending up leaves above the water surface, where they can absorb carbon dioxide directly from the air. The submerged leaves are larger and thinner than the aerial ones.

Nutrient availability

The photosynthetic pigments – usually chlorophyll – are produced by the plant within the cells. To do this, a number of nutrients are required, including magnesium (Mg), potassium (K), iron (Fe) and nitrogen (N). These nutrients, and others indirectly, are vital for the production and continual use of photosynthetic pigments and the cells containing them. A general lack of any of these nutrients can often be seen as a fading or change in leaf colour, as the production of chlorophyll pigment is affected.

Photosynthesis and leaf colour

The colour of an object that we perceive is produced by pigments that reflect certain wavelengths of light. A green pigment will absorb most of the light spectrum except for the green areas, which are reflected, making the object appear green. The green photosynthetic pigment in most plants is chlorophyll and is contained in structures called chloroplasts within the plants’ cells. Chlorophyll is produced in the greatest quantities in the parts of the plant that receive the most light, mainly in the leaves. The roots of plants receive virtually no light below the substrate, so do not contain chlorophyll and hence, do not appear green.

As we have seen earlier, plants have very little control over the rate of photosynthesis within their own cells and simply photosynthesise at the fastest rate possible, depending on environmental conditions. In bright conditions, a plant may receive more light than it needs to produce adequate amounts of glucose. If this happens continually in the plant’s habitat, it may develop another method of photosynthesising at a slower rate.

This often involves using a different photosynthetic pigment, which may be less efficient at breaking down water for photosynthesis. These secondary pigments are called carotenoids and vary in colour from pale yellow to dark red.

Depending on the light conditions normally experienced by a plant, the leaves will vary in colour and may appear various shades of green, brown, orange or red. Some plants will always keep the same colour, while others may be able to vary their colour depending on the light conditions. In the aquarium, looking at the leaf colour of a plant can help to establish what kind of light is required by the plant. A plant that produces reddish leaves may be accustomed to bright light conditions in nature and will need the same conditions in the aquarium to photosynthesise properly. Sometimes, red plants first produce green leaves, which then change to red. If they stop turning red or revert back to green, this may indicate that the intensity of light in the aquarium is not sufficiently high. Alternatively, in very bright conditions, green plants may start to produce red leaves, but this should not be taken as an indication that the light is too bright.

Some plants, particularly within the cryptocoryne group, produce brown leaves. These plants are often found in shallow streams with overhanging vegetation and may have developed the use of photosynthetic pigments that are more efficient at using the green areas of the light spectrum. These may be more abundant in an environment shaded by other plants. Therefore, plants with brown leaves should do relatively well in shaded areas of the aquarium. In many cases, brown-leaved cryptocorynes will develop green leaves when kept in brightly lit areas of the aquarium. This colour change occurs because of the change in light spectrum from the plant’s natural environment. A green photosynthetic pigment such as chlorophyll may become more useful to the plant than its previous photosynthetic pigments.

Alternanthera reineckii has a distinctive red-brown leaf colour. A red photosynthetic pigment is less efficient at utilising light energy, a sign that this plant requires strong lighting.

Echinodorus ‘Rubin’ produces large, brownish leaves and may be able to utilise green light more efficiently than other plants. This is particularly useful in shaded areas.

The mottled green-and-red leaf of this Echinodorus indicates that there are two separate photosynthetic pigments. In bright light, the less efficient red pigment helps to reduce the rate of photosynthesis, while in low light, the green pigment will spread and increase the efficiency of photosynthesis.

Respiration and oxygen levels

The process of respiration occurs