Fishkeeping

Fishkeeping: Origins, Types of Fishkeeping Systems, Aquarium Maintenance, Water Conditions, and Nitrogen Cycle

Fishkeeping is a popular hobby that involves keeping fish in a home aquarium or garden pond, with a piscicultural fishkeeping industry serving as a branch of agriculture.
Fish have been kept for both functional and decorative purposes for thousands of years, with some cultures using wild-caught fish in ponds for food, while others valued brightly colored or tame fish as pets.
Freshwater fishkeeping is the most popular branch of the hobby, with community tanks containing a variety of compatible species and single-species breeding aquaria being popular. Livebearing fish such as mollies and guppies are among the easiest to raise in captivity, but aquarists also breed many types of cichlid, catfish, characins, cyprinids, and killifish.
Marine aquaria have more specific needs and requirements to maintain, and the livestock is generally more expensive. Marine aquarists often attempt to recreate a coral reef in their aquaria using large quantities of living rock, porous calcareous rocks encrusted with coralline algae, sponges, worms, and other small marine organisms.
Brackish water aquaria combine elements of freshwater and saltwater systems, with salinity that must stay between that of freshwater and seawater. Brackish water fish come from habitats with varying salinity, such as mangroves and estuaries.
Basic aquarium maintenance should generally be performed weekly to maintain optimum conditions for fish and plants. Balance is facilitated by larger volumes of water which dilute the effects of a systemic shock. Water temperature can be regulated with a combined thermometer and heating or cooling unit.
The solute content of water is perhaps the most important aspect of water conditions, with salt content, or salinity, being the most basic classification of water conditions. Several other water characteristics, such as hardness, dissolved organic content, and dissolved gases content, are also important factors.
Fish, invertebrates, fungi, and some bacteria excrete nitrogen in the form of ammonia and must then pass through the nitrogen cycle. Nitrogen waste products become toxic to fish and other aquarium inhabitants above a certain concentration. Nitrogenous waste is metabolized in aquaria by a group of bacteria known as nitrifiers, with nitrifying bacteria metabolizing ammonia into nitrite, which is highly toxic to fish, and another type of bacteria converting this nitrite into the less toxic compound, nitrate.
Although called the nitrogen "cycle" by hobbyists, in aquaria, the cycle is not complete: nitrogen must be added (usually indirectly through food) and nitrates must be removed at the end. Nitrogen bound up in plant matter is removed when the plant grows too large. Activated carbon filters absorb nitrogen compounds and other toxins from the water, while biological filters provide a medium specially designed for colonization by the desired nitrifying bacteria.Aquarium Fishkeeping
The nitrogen cycle in aquariums is essential for maintaining healthy fish and plant life.
New tanks need to mature before stocking them with fish to avoid "New Tank Syndrome".
Efficient filtration is vital in maintaining a healthy aquarium, with the largest bacterial populations inhabiting the filter.
Tank size and capacity are important factors to consider, with surface area and oxygen levels being limiting factors.
Fishkeeping is a multibillion-dollar industry, with the United States being the largest market.
Animal welfare is a concern in fishkeeping, with inexperienced aquarists often keeping fish in inadequate conditions.
Fish breeding is a popular challenge in the hobby, with some species requiring special conditions to breed.
The aquarium trade threatens fish habitats through pollution, commercial fishing, and the introduction of invasive species.
Coral reefs are threatened by the aquarium trade through destructive fishing techniques and the depletion of rare species.
Cyanide is used to stun and immobilize fish during collection, causing irreversible damage or death to the target and other species.
Captive breeding and aquaculture can help reduce the impact on wild stocks, preserve rare or extinct species, and provide valuable ecological and behavioral data.
Captive breeding has reduced prices for hobbyists, but cultured animals remain controversial.Issues in the Tropical Fish Industry
The tropical fish industry is a multi-billion dollar global business.
The industry is highly unregulated, with many tropical fish being caught using cyanide or other harmful methods.
The use of cyanide in the industry has been linked to coral reef destruction and harm to other marine life.
Many fish are bred in captivity, but this has led to inbreeding and genetic problems.
Selective breeding has led to wider variation within species, creating more diverse commercial stocks.
Invasive species can occur when tropical fish are released into non-native waters, disrupting the local habitat.
Humane treatment of fish during transport is becoming a concern, with regulations being put in place to control harvesting and shipping practices.
The Maui County Council passed a measure in 2011 requiring aquarium fisheries to adopt humane practices for preparing fish for transport to market.
The regulations include prohibiting clipping the fins on fish, outlawing puncturing swim bladders, and prohibiting "starving" the fish.
The measure also requires that shippers file mortality reports on the animals they ship.
The tropical fish industry is a complex and controversial industry that requires more regulation and attention to animal welfare.
Consumers can make a difference by purchasing fish from sustainable sources and supporting humane practices.