The substrate of an aquarium refers to the material used on the tank bottom. It can affect water chemistry, filtration, and the well-being of the aquarium's inhabitants, and is also an important part of the aquarium's aesthetic appeal. The appropriate substrate depends on the type of aquarium; the most important parameter is whether the aquarium contains fresh water or saltwater.
Substrates are added to most aquaria principally for the increase in beneficial bacteria this provides. However, substrates can also have a variety of direct effects on water quality by releasing substances into the water, absorbing substances from the water, or reacting chemically with substances from other sources. Substrates can also have indirect effects on a system's health; dark-colored substrates, for example, are considered by some to be better for fish, as the fish display more colorfully by comparison, and are less likely to behave timidly. [1] [2] Apart from all other considerations, substrates are frequently chosen for their aesthetic qualities.
Some substrates are used to alter water chemistry. Crushed coral and coral sand both contain calcium carbonate, which will raise the carbonate hardness and buffer the pH. Peat may be used in some aquaria to mimic some soft water habitats.
Substrate may also be used as part of a biological filtration system. Beneficial bacteria colonize all aquarium surfaces that are exposed to aerated water, including the substrate. Because the numerous particles have a high surface area, substrates are often employed in biological filtration. Some common types of filtration involving the substrate include the undergravel filter and the deep sand bed.
Planted tanks require a substrate that will remain loose enough for plant roots to penetrate it. The substrate should be chemically inert and free of sharp edges. Fine gravel (1–2 mm) is preferred by some aquarists because coarser substrates allow debris to settle within the gaps between grains, which is particularly difficult to clean in a planted aquarium. Sloping the substrate so it is most shallow in front accommodates larger plants with correspondingly larger root systems in the back. The substrate for plants should be at least 5 cm (2 in) deep. Often, a lower layer of richer substrate such as potting soil, peat, vermiculite, or certain types of clay are used as a source of iron and trace elements for plant roots. [3] [4]
In breeding tanks for egg-scattering species, a layer of marbles is sometimes used as a substrate, allowing the eggs to fall into the gaps between the marbles where the parents cannot eat them. [5] Quarantine tanks (sometimes called hospital tanks) often use no substrate at all. This assists in keeping the aquarium as clean as possible as well as monitoring of fish excrements. [6]
Fish of the species Pelvicachromis taeniatus were shown to be able to recognize olfactory traces left behind by substrate, even in clear water; highlighting that the presence of substrate is important for fish kept in tanks. This method is beneficial to increase fish activity drastically in empty tanks. [7]
For freshwater aquaria, gravel is the most common substrate. To prevent damage to fish, gravel should not be sharp. Aquarium gravel can be as coarse as pea-sized or as fine as 1–2 mm. [1] It is available in a number of colors, and may be naturally colored or dyed, and may have a polymer seal to ensure it does not affect water chemistry. [1] Gravel sold specifically for use in aquaria is chemically inert. It is commonly composed of quartz or other lime-free minerals. [4] If the gravel is rough or sharp, it is not suitable for bottom-dwelling fish that like to sift the substrate or dig. [1] When growing aquatic plants, the Cation Exchange Capacity [8] (CEC) is also an important thing to consider when choosing a substrate. CEC is the ability to absorb positively charged nutrient ions (so high CEC is good). This means the substrate will hold nutrients and make them available for the plant roots. It doesn't indicate the amount of nutrients the substrate contains.
Shell grit, crushed limestone, crushed marble, crushed coral skeletons, coral sand, and oolitic aragonite substrates are possible choices. Because calcium carbonate, the primary component of these substrates, increases water hardness and pH, these are used most often for hard water species, such as those for African rift lake cichlids or for saltwater fish and invertebrates. Some invertebrates such as mollusks or stony corals also use the calcium and strontium released. Calcium carbonate substrates are poorly suited to aquaria housing most other freshwater aquarium fish, particularly river species, which are adapted to soft water. [4]
Peat, or decomposed plant matter, is used most commonly in soft water or blackwater river [9] systems, such as those mimicking the Amazon River [10] basin. In addition to being soft in texture and therefore suitable for demersal (bottom-dwelling) species such as Corydoras catfish, peat is reported to have a number of other beneficial functions in freshwater aquaria. It softens water by acting as an ion exchanger, it contains substances good for plants and for the reproductive health of fishes, and can even prevent algae growth and kill microorganisms. Peat often stains the water yellow or brown due to the leaching of tannins. [4]
Sand is often recommended for use with certain species, such as the river stingrays of family Potamotrygonidae, which bury themselves in the fine substrate. However, these species can be successfully kept with coarser substrates as well. Clay can be mixed in with sand to provide extra nutrients for live plants.
A growing aquarist substrate is the use of leaves in an aquarium in replacement for traditional substate. The leaf or leaves can be mixed with other substrates or solely on their own. They mimic the natural environments of aquatic creatures and create a stress free and pH balancing environment for flora and fauna by tinting the water column colour to a reddish hue with the release of beneficial tannin that certain aquatic life prefer. [11] They are often used in blackwater aquarium biotopes. [12] Care has to be taken as some leaf matter may be poisonous in nature and harmful to aquatic life.
In some aquaria, different substrates are used in different parts of the tank. For example, peat can be used in one corner, while gravel in another portion allows rooted plants. [4]
The fiveband barb is a species of cyprinid freshwater fish from Southeast Asia. This species is restricted to blackwater streams and peat swamps in northwestern Borneo and possibly Peninsular Malaysia, but it has often been confused with the more widespread, closely related D. hexazona, which is similar except that it lacks the black spot at the rear base of the dorsal fin seen in D. pentazona.
A vivarium is an area, usually enclosed, for keeping and raising animals or plants for observation or research. Often, a portion of the ecosystem for a particular species is simulated on a smaller scale, with controls for environmental conditions.
A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment. A reef aquarium requires appropriately intense lighting, turbulent water movement, and more stable water chemistry than fish-only marine aquaria, and careful consideration is given to which reef animals are appropriate and compatible with each other.
A marine aquarium is an aquarium that keeps marine plants and animals in a contained environment. Marine aquaria are further subdivided by hobbyists into fish only (FO), fish only with live rock (FOWLR), and reef aquaria. Fish only tanks often showcase large or aggressive marine fish species and generally rely on mechanical and chemical filtration. FOWLR and reef tanks use live rock, a material composed of coral skeletons harboring beneficial nitrogen waste metabolizing bacteria, as a means of more natural biological filtration.
A constructed wetland (CW) is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development. Constructed wetlands are engineered systems that use natural functions vegetation, soil, and organisms to provide secondary treatment to wastewater. The design of the constructed wetland has to be adjusted according to the type of wastewater to be treated. Constructed wetlands have been used in both centralized and decentralized wastewater systems. Primary treatment is recommended when there is a large amount of suspended solids or soluble organic matter.
Tropical fish are generally those fish found in aquatic tropical environments around the world. Fishkeepers often keep tropical fish in freshwater and saltwater aquariums. The term "tropical fish" is not a taxonomic group, but rather is a general term for fish found in such environments, particularly those kept in aquariums.
The Berlin Method of biological filtration is a method for maintaining a clean and stable environment within a saltwater aquarium, typically a coral reef system. This method relies on the use of ample live rock. The theory is that aerobic bacteria covering the surface of the porous live rock and sand convert harmful ammonia into nitrites, then nitrates, which are much less harmful to the tank's inhabitants. Through the process of diffusion, the nitrates move deep within the rock where they are converted by anaerobic bacteria to free nitrogen gas. Left over nitrates are removed through regular partial water changes, or with algal filtration such as an algae scrubber. As an added measure, a protein skimmer is used to remove some of the dissolved organic compounds before they break down into ammonia, although skimmers do not remove ammonia from fish urea.
Community aquaria are tanks that are designed to contain more than one species of fish. Most commonly they include a variety of species that do not normally occur together in nature, for example angelfish from Brazil, swordtails from Mexico, and gouramis from South East Asia. The aim of such communities is to bring together fish that are compatible in temperament and water requirements, while using their different colours and behaviors to add interest and entertainment value.
Aquascaping is the craft of arranging aquatic plants, as well as rocks, stones, cavework, or driftwood, in an aesthetically pleasing manner within an aquarium—in effect, gardening under water. Aquascape designs include a number of distinct styles, including the garden-like Dutch style and the Japanese-inspired nature style. Typically, an aquascape houses fish as well as plants, although it is possible to create an aquascape with plants only, or with rockwork or other hardscape and no plants.
Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, as a branch of agriculture.
The croaking gourami is a species of small freshwater labyrinth fish of the gourami family. They are native to still waters in Southeast Asia and are distributed worldwide via the aquarium trade. Croaking gouramis are capable of producing a "croaking" noise using their pectoral fins.
A brackish-water aquarium is an aquarium where the water is brackish (semi-salty). The range of "saltiness" varies greatly, from near freshwater to near marine and is often referred to as specific gravity (SG) or salinity. Brackish water aquaria is a popular specialization within the fishkeeping hobby. Many species of fish traded as freshwater species are actually true brackish species, for example mollies, Florida flagfish, and some cichlids such as chromides and black-chin tilapia. There are also several popular species traded purely as brackish water fish, including monos spp, scats, archerfish, and various species of pufferfish, goby, flatfish, and gar. Generally, aquarists need to maintain a specific gravity of around 1.005 to 1.010 depending on the species being kept, but practically all brackish water fish tolerate variations in salinity well, and some aquarists maintain that regularly fluctuating the salinity in the aquarium actually keeps the fish healthy and free of parasites.
In fishkeeping, a refugium is an appendage to a marine, brackish, or freshwater fish tank that shares the same water supply. It is a separate sump, connected to the main show tank. It is a "refugium" in the sense that it permits organisms to be maintained that would not survive in the main system, whether food animals, anaerobic denitrifying bacteria, or photosynthesizers. For some applications water flow is limited in order to protect plants or animals that require slow flow. The refugium light cycle can be operated opposite to the main tank, in order to keep total system pH more stable (due to the uptake of acid-forming CO2 by photosynthesis occurring in the refugium during its "daylight" hours). One volume guideline for a refugium is 1:10 main tank volume.
Aquarium filters are critical components of both freshwater and marine aquaria. Aquarium filters remove physical and soluble chemical waste products from aquaria, simplifying maintenance. Furthermore, aquarium filters are necessary to support life as aquaria are relatively small, closed volumes of water compared to the natural environment of most fish.
A freshwater aquarium is a receptacle that holds one or more freshwater aquatic organisms for decorative, pet-keeping, or research purposes. Modern aquariums are most often made from transparent glass or acrylic glass. Typical inhabitants include fish, plants, amphibians, and invertebrates, such as snails and crustaceans.
Sand-based athletic fields are sports turf playing fields constructed on top of sand surfaces. It is important that turf managers select the most suitable type of sand when constructing these fields, as sands with different shapes offer varied pros and cons. Regular maintenance of sand-based athletic fields is just as important as the initial construction of the field. As water and other aqueous solutions are added, a layer of thatch may accumulate on the surface of the turf. There are different ways to manage this level of thatch, however the most common are aeration and vertical mowing.
An aquarium is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquatic reptiles, such as turtles, and aquatic plants. The term aquarium, coined by English naturalist Philip Henry Gosse, combines the Latin root aqua, meaning 'water', with the suffix -arium, meaning 'a place for relating to'.
Several species of sharks are kept in captivity in public aquaria. In home aquaria, size constraints mean that only the smallest sharks are typically viable as pets.
Apistogramma panduro (A-183), also commonly referred to as Apistogramma pandurini, is a small species of freshwater fish, a cichlid from the Amazon river basin in Peru. This dwarf cichlid is closely related to Apistogramma nijsseni, so much so that they are placed in the Apistogramma nijessni species group. Some common names for Apistogramma panduro are Blue Panda Apisto and Panduros’ apisto.
An algae scrubber is a water filtering device which uses light to grow algae; in this process, undesirable chemicals are removed from the water. Algae scrubbers allow saltwater, freshwater and pond hobbyists to operate their tanks using natural filtration in the form of primary production, much like oceans and lakes.