Glossary

Fish Species

Barb (Family Cyprinidae) – a diverse family of freshwater fish found in Asia, Africa, and Europe. Barbs are known for their sharp dorsal and pectoral fins, which are used for defense and dominance displays. They are generally active and social fish that enjoy schooling.
Cichlid (Family Cichlidae) – a very large and diverse family of freshwater fish found in Africa, South America, and Central America. Cichlids are known for their complex social behaviors, bright colors, and varied diets. They come in a wide range of sizes and shapes, and many species are popular aquarium fish.
Guppy (Poecilia reticulata) – a small, livebearing fish native to South America. Guppies are known for their bright colors, ease of breeding, and peaceful nature. They are popular aquarium fish for beginners and experienced hobbyists alike.
Read: Guppy Fish
Koi (Cyprinus carpio koi) – a domesticated form of common carp (Cyprinus carpio) that is selectively bred for its colorful scales. Koi are popular ornamental fish that are often kept in outdoor ponds. They are relatively hardy and can tolerate a wide range of water temperatures and conditions.
Livebearer (Suborder Poecilioidei) – a group of fish that give birth to live young rather than laying eggs. Livebearers are known for their ease of breeding and their ability to quickly populate an aquarium. Some popular livebearer species include guppies, mollies, platies, and swordtails.
Molly (Poecilia sphenops) – a small, livebearing fish native to the Caribbean Sea and the Gulf of Mexico. Mollies are known for their thick bodies, peaceful nature, and ease of care. They are popular aquarium fish for beginners and experienced hobbyists alike.
Read: Molly Fish
Rasbora (Genus Rasbora) – a genus of small, schooling fish found in Southeast Asia. Rasboras are known for their peaceful nature, small size, and active swimming behavior. They are popular aquarium fish for adding movement and color to a community tank.
Read: Harlequin rasboras
Xenotoca eiseni (Also known as the Mexican cavefish) – a species of livebearer fish that is native to Mexico. Mexican cavefish are blind and have lost their pigmentation due to their life in dark caves. They are popular aquarium fish for their unique appearance and interesting evolutionary history.

Plants

Aquatic Moss (Genus Riccia) – a type of non-vascular plant that thrives in moist or aquatic environments. Aquatic moss is commonly used in aquascaping due to its delicate appearance, ability to attach to various surfaces, and ease of care.
Java Fern (Microsorum pteropus): a hardy freshwater plant native to Southeast Asia. Java fern is popular in aquariums for its attractive foliage, adaptability to various water conditions, and tolerance for low light levels. It can be attached to rocks or driftwood using fishing line or thread, allowing it to grow without interfering with the substrate.
Jungle Val (Vallisneria spiralis) – a popular aquatic plant known for its long, grass-like leaves. Jungle val is a fast-growing plant that provides dense cover for fish and helps to oxygenate the water. It is relatively easy to care for and can be grown in a variety of aquarium setups.
Live Plants (Broad term) – aquatic plants that provide various benefits to an aquarium ecosystem. Live plants contribute to water purification by removing harmful substances like carbon dioxide and ammonia, helping to maintain healthy water quality. They also provide shade, oxygen, and hiding places for fish, enhancing their overall health and well-being. Additionally, live plants enhance the aesthetic appeal of an aquarium, creating a more natural and visually appealing habitat for the fish.

Aquarium Types

Aquarium – a tank or bowl designed to house fish, aquatic plants, and other aquatic animals. Aquariums can range in size from small bowls to large tanks, and they can be made from a variety of materials, including glass, acrylic, and plastic.
Community Tank – An aquarium that houses multiple species of fish that are compatible with each other. Community tanks are a popular choice for beginners and experienced hobbyists alike, as they allow for a diverse array of fish to be kept together.
Nano Tank – A very small aquarium, typically under 10 gallons. Nano tanks are a good option for beginners or those with limited space, as they are relatively easy to maintain. However, nano tanks can still be home to a variety of interesting fish species.
Quarantine Tank – A separate tank used to isolate new or sick fish to prevent the spread of disease. Quarantine tanks are essential for preventing the introduction of harmful pathogens into an aquarium community.
Species Tank – an aquarium devoted to a single species of fish. Species tanks are a good option for those who want to focus on the care and breeding of a particular species. Species tanks can be very beautiful and peaceful, and they can be a great way to learn about the natural habitats of different fish.

Equipment & Accessories

Aeration – the process of increasing the oxygen saturation in the water, often achieved with air pumps and air stones, which introduce bubbles that bring oxygen into the water column. Aeration is essential for fish to breathe and is especially important for fish that require high levels of oxygen, such as labyrinth fish like bettas.
Air Pump – a device used to provide air to an aquarium, typically for aeration. Air pumps can be powered by electricity or batteries.
Biological Filter – a type of aquarium filter that uses beneficial bacteria to convert toxic waste products, such as ammonia and nitrite, into less harmful nitrate. Biological filters are essential for maintaining healthy aquarium water and are typically part of a multi-stage filtration system.
Canister Filter – a type of external filter that houses a variety of filtration media, including mechanical, biological, and chemical filtration media. Canister filters are efficient and can handle large volumes of water.
Carbon Dioxide (CO2) System – a system used to introduce carbon dioxide gas into an aquarium, which is necessary for the photosynthesis of aquatic plants. Carbon dioxide is often injected into planted aquariums to increase plant growth and enhance the overall health of the ecosystem.
Dip Net – a small net used for catching or handling fish. Dip nets are typically made of soft mesh or plastic to avoid harming the fish.
Filtration System – a combination of filtration methods used to clean the water in an aquarium by removing toxins, waste, and other unwanted materials. Filtration systems typically include mechanical, biological, and chemical filtration stages.
Heater – a device used to maintain a stable and appropriate temperature in the aquarium. Most aquarium fish have specific temperature preferences, and heaters ensure that the water temperature remains within a safe range.
Read more: best aquarium heaters
Hydrometer – a device used to measure the specific gravity or salinity of water. Specific gravity is a measure of the density of the water, which is important for maintaining the proper balance of minerals and nutrients for fish and aquatic plants.
Lighting – an essential component of any aquarium, providing light for plant growth and enhancing the visual appeal of the aquarium. The type of lighting used depends on the specific plants and fish being kept.
Live Rock – rock collected from the ocean that is used in saltwater aquariums. Live rock provides a variety of benefits, including harboring beneficial bacteria, adding calcium and other minerals, and providing hiding places for fish.
Protein Skimmer – a device used in saltwater aquariums to remove organic compounds, such as proteins and lipids, from the water. Protein skimmers help to maintain water clarity and prevent the buildup of harmful toxins.
Siphon – a tool used for water changes and cleaning the substrate. Siphons are typically made of flexible tubing and a valve to control the flow of water.
Sponge Filter – a simple, air-driven filter that is suitable for fry and small fish. Sponge filters provide mechanical and biological filtration and are relatively inexpensive and easy to maintain.
Substrate – the material that lines the bottom of the aquarium. It provides a base for plants, décor, and provides a place for fish to rest. Substrate options include sand, gravel, and specialized substrates for plant growth.
Thermometer – a device used to measure the temperature of aquarium water. Accurate temperature monitoring is crucial for maintaining the health of the fish and ensuring that the water is at an appropriate temperature for the fish species being kept.
UV Sterilizer – a device that uses ultraviolet light to kill harmful bacteria and parasites in aquarium water. UV sterilizers are often used in conjunction with other filtration methods to maintain water quality.
Vacuum – a tool used for cleaning the substrate and performing water changes. Vacuums help to remove debris and waste from the substrate, which helps to maintain water quality and prevent the buildup of harmful substances.
Valve – a device used to control water flow in aquarium equipment. Valves are often used to adjust the flow rate of filters and pumps.
Wavemaker – a device used to create water movement in an aquarium. Wavemakers help to distribute oxygen throughout the water column and can also help to stimulate fish activity.
Water Conditioner – a chemical treatment used to remove chlorine and chloramines from tap water before adding it to the aquarium. Chlorine and chloramines can be harmful to fish, so it is essential to treat tap water before using it in the aquarium.
Water Test Kit – a set of tools and reagents used to measure various water parameters, such as pH, hardness, ammonia, nitrite, and nitrate. Regular water testing is essential for maintaining healthy aquarium water and preventing water quality issues.
Read more: How to test fish tank water

Water Chemistry & Maintenance

Algae – simple, non-flowering aquatic plants that can grow rapidly in aquariums. While some algae are beneficial, excessive growth can deplete nutrients, reduce water clarity, and produce toxins that harm fish.
Alkalinity – the ability of water to resist changes in pH. Alkalinity helps to buffer the pH and prevent sudden swings in acidity or alkalinity. Most freshwater fish prefer a stable pH range between 6.5 and 8.0.
Ammonia – a highly toxic waste product produced by fish and decomposing organic matter. High levels of ammonia can cause ammonia poisoning, which can be fatal to fish.
Calcium – an essential mineral for fish, invertebrates, and plants. Calcium is important for bone structure, shell formation, and various physiological processes.
Chlorine – a chemical disinfectant found in tap water that can be harmful to fish. Chlorine and chloramines, another disinfectant commonly used in tap water, should be removed from tap water before adding it to the aquarium using a water conditioner.
Cycling – the process of establishing a colony of beneficial bacteria in the aquarium to convert ammonia and nitrite into less harmful nitrates. This process takes several weeks and is crucial for maintaining healthy aquarium water.
Detritus – fine organic debris, such as uneaten food, fish waste, and decaying plant matter, that accumulates at the bottom of the aquarium. Detritus can decompose and release ammonia, so it is important to remove it regularly through gravel vacuuming and water changes.
Diatoms – a type of algae that is common in newly established aquariums. Diatoms typically appear as brown or yellow spots or patches on the aquarium glass or décor. They are generally harmless and typically disappear as the aquarium matures.
Dissolved Oxygen (DO) – the amount of oxygen dissolved in aquarium water. Fish require oxygen to breathe, and low DO levels can lead to suffocation. Aeration, filtration, and maintaining proper water temperature help to maintain adequate DO levels.
GPH (Gallons Per Hour) – a measurement of the flow rate of an aquarium filter. A filter’s GPH rating indicates how much water it can process per hour.
Hardness – the measure of dissolved calcium and magnesium in aquarium water. Hard water has higher levels of calcium and magnesium, while soft water has lower levels. Most freshwater fish prefer moderately hard water.
Ichthyology – the scientific study of fish, including their anatomy, physiology, behavior, and evolution.
Nitrate – a byproduct of the nitrogen cycle that is relatively less harmful to fish than ammonia or nitrite. However, high levels of nitrates can still stress fish and promote algae growth. Regular water changes are essential to control nitrate levels.
Nitrogen Cycle – a crucial process in aquariums that converts toxic ammonia and nitrite into less harmful nitrates. The nitrogen cycle is initiated by the growth of beneficial bacteria in the filter media and on surfaces within the aquarium.
Osmosis – the movement of water molecules from a less concentrated solution to a more concentrated solution through a semipermeable membrane. Osmotic pressure plays a role in maintaining water balance within the fish’s body.
Oxygenation – the process of increasing the amount of dissolved oxygen in aquarium water. Aeration, filtration, maintaining proper water temperature, and using plants can help to oxygenate the aquarium.
pH Level – a measure of how acidic or alkaline the water is. The pH scale ranges from 0 (extremely acidic) to 14 (extremely alkaline). Most freshwater fish prefer a neutral pH between 6.5 and 8.0.
Salinity – the amount of dissolved salts in water. Marine aquariums require a specific salinity level, which is typically higher than freshwater aquariums.
Tannins – organic compounds released by driftwood or other botanical materials. Tannins can impart a brown or yellow color to the aquarium water and may affect the growth of some plants.
Trace Elements – essential minerals required in small quantities for the health of fish, invertebrates, and plants. Trace elements often include iron, manganese, copper, and other trace minerals.
Water Change – the process of replacing a portion of aquarium water with fresh, conditioned water. Water changes are essential for maintaining healthy water quality and removing accumulated waste products.
Zeolite – a natural mineral that can be used in filters to absorb ammonia, nitrites, and other harmful substances. Zeolite can help to detoxify the aquarium water and maintain stable water parameters.

Feeding & Nutrition

Flake food – a type of fish food made from compressed flakes of various fishmeals, plant matter, and other additives. Flake food is a versatile and readily available option for a wide range of fish species.
Overfeeding – providing fish with more food than they can consume in a single feeding. Overfeeding can lead to water quality issues, such as ammonia and nitrite spikes, as well as digestive problems in fish.
Pellet food – a type of fish food made from small, compressed pellets of various ingredients. Pellet food is a more concentrated form of nutrition than flake food, making it suitable for larger fish or those with slower metabolisms.
Plankton – a diverse group of microscopic organisms that float freely in the water column. Plankton can be a valuable source of food for many aquarium fish, especially those that are omnivorous or herbivorous.
Zooplankton – a subset of plankton consisting of small, floating animals. Zooplankton are a vital source of food for many aquarium fish, especially fry and juvenile fish.

Health & Disease

Camallanus worms – a type of parasitic roundworm that can infect fish, particularly livebearers. Camallanus worms can cause a variety of symptoms, including lethargy, loss of appetite, and abdominal swelling.
Euthanize – to humanely end the life of an animal, such as a fish, to avoid suffering. Euthanization is typically performed by a veterinarian or an experienced fishkeeper using a method that ensures minimal pain or distress for the animal.
Gill flukes – a type of parasitic flatworms that infect the gills of fish. Gill flukes can cause a variety of symptoms, including labored breathing, lethargy, and loss of appetite.
Parasite – an organism that lives on or in another organism, known as the host, and gets its food or other resources from the host. Parasites can cause a variety of health problems in fish, ranging from mild discomfort to severe illness or death.

Aquascaping & Decoration

Aquascaping – the art of arranging aquatic plants, rocks, stones, cavework, or driftwood, in an aesthetically pleasing manner within an aquarium. Aquascaping can significantly enhance the visual appeal of an aquarium and create a more natural habitat for the fish.
Hardscape – the non-living decorations in an aquarium, such as rocks, stones, and driftwood. Hardscape can provide visual interest, create hiding places for fish, and help to maintain water quality by providing beneficial bacteria habitat.

Fishkeeping Concepts & Procedures

Acclimation – the process of gradually introducing fish to new water conditions, especially when adding them to an established aquarium. This helps to minimize stress and prevent shock.
Bacterial bloom – a sudden increase in the population of beneficial bacteria in the aquarium, often causing a cloudy appearance in the water. This is usually a sign that the aquarium is cycling and the nitrogen cycle is establishing itself.
Ecosystem – the self-sustaining community of organisms living in the aquarium, including fish, plants, and microorganisms. The balance of the ecosystem is crucial for maintaining healthy water quality and fish health.
Egg scatterer – fish that release their eggs into the water column rather than attaching them to a surface. This type of egg dispersal increases the chances of fertilization and survival.
Finned – having fins, the appendages on fish used for movement, balance, and communication.
Fry – newly hatched fish, often requiring specialized care and feeding to survive until they are large enough to fend for themselves.
In situ – a Latin phrase meaning “in position” or “within the context.” In aquariums, it refers to examining or treating something inside the aquarium without removing it from the water.
Invertebrates – animals that lack a backbone, such as snails, shrimp, crabs, and worms. They play a vital role in the aquarium ecosystem, consuming detritus and algae, and providing food for fish.
Lateral line – a sensory system on fish that detects movement and vibrations in the water. It helps fish navigate, detect predators, and communicate with each other.
Macroalgae – large, photosynthetic algae that can be used in marine and freshwater aquariums. They provide a source of food and shelter for fish, invertebrates, and microorganisms.
Omnidirectional flow – water movement that occurs in all directions within the aquarium, often used in reef tanks to ensure efficient water circulation and distribution of nutrients.
Omnivore – fish that consume both plant and animal matter. This diet provides them with a balanced source of nutrients.
Quarantine procedure – isolating new or sick fish in a separate tank to prevent the spread of diseases or parasites to the main aquarium.
Stocking density – the number of fish kept in an aquarium relative to its size. Overstocking can overload the filtration system, deplete oxygen, and increase the risk of disease.
Ventilation – the process of exchanging air in and around the aquarium to prevent the buildup of harmful gases, such as carbon dioxide. This is particularly important for aquariums with high numbers of fish or dense vegetation.
Water flow – the movement of water within the aquarium, driven by filtration systems, air pumps, and water circulation pumps. Proper water flow is essential for maintaining healthy water quality and fish health.

Miscellaneous

Brackish water – water that contains a mixture of freshwater and saltwater. It is suitable for a variety of fish species that require a balance of salinity.
Demersal – fish that inhabit the lower portions of the aquarium, often living near the substrate or on the bottom.
Fluoride – a chemical sometimes added to aquarium substrates to promote plant growth. However, it should be used carefully as excessive fluoride can harm fish.
Lumen – a unit of light intensity used to measure the amount of light emitted by a light source. In aquariums, it is used to determine the appropriate lighting requirements for plants and fish.
Yabby – a type of freshwater crayfish that is sometimes kept in aquariums. They can be an interesting addition to the ecosystem and provide a source of food for larger fish.