aquarium cold water fish

Butterfly Koi, Longfin Koi, or Dragon Carp coldwater aquarium fish are a type of ornamental fish notable for their elongated finnage. The fish are a breed of the common carp, Cyprinus carpio, which includes numerous wild carp races as well as domesticated koi ("Nishikigoi").

The European Bullhead aquarium cold water fish, Cottus gobio, is a fish of the Cottidae family that is widely distributed in Europe. It is a type of sculpin and has two alternative names: miller's thumb and tommy logge. 

Picture of European Bullhead

The Fathead Minnow aquarium cold water fish (Pimephales promelas), is a species of temperate freshwater fish belonging to the Pimephales genus of the cyprinid family. The natural geographic range extends throughout much of North America, from central Canada south along the Rockies to Texas, and east to Virginia and the Northeastern United States. This minnow has also been introduced to many other areas via bait bucket releases. Its golden, or xanthic strain, known as the rosy-red minnow, is a very common feeder fish sold in the United States. This fish is best known for producing Schreckstoff. 

The fathead aquarium cold water fish is quite tolerant of turbid, low-oxygentated water, and can be found in muddy ponds and streams that might otherwise be inhospitable to other species of fish. It can also be found in small rivers

Generally only the rosy-red variety is sold in pet shops (though very often several wild types come in with each shipment), and is summarily the most likely to be found in an aquarium. These fish are social, active, and moderately hardy. Like most cyprinids, they will accept almost any type of food. They can be bred in an aquarium, and it should be noted that the fathead minnow aquarium cold water fish is one of the only cyprinids that protects its eggs in the nest (carried out by the male). Fatheads will live about two years if they have spawned, but significantly longer (potentially up to four years) if they have not. These fish prefer a temperature of 10 - 21 °C (50 - 70 °F) and a pH range of 7.0 - 7.5.

The Gold Barb, aquarium cold water fish a gold colour variant of the China Barb, is an active, peaceful schooling species that spends most of its time in the mid-level and bottom of the water. Its typical lifespan in captivity is around four to six years. This peaceful green-gold fish is often used in community tanks by fish keeping hobbyists. It flocks breed readily in outdoor pools and free-standing ponds during summer months, and withstands cooler temperatures better than other tropical fish. However, it does not stand the cold as well as its original plainer China barb counterparts. Albino variants of the Gold barb aquarium cold water fish have been produced by Dennis Wilcox in the 1970s in the US. Gold barbs with no black markings have been observed by Stanislav Frank in Europe also around that time.

Beautiful Gold Barb Images

The Koi aquarium cold water fish, or the common carp, is a hardy fish, and koi retain that durability. Koi are cold-water fish, but benefit from being kept in the 15-25 degrees C range and do not react well to long cold winter temperatures, their immune system 'turning off' below 10 degrees C. Koi ponds have a meter or more of depth in areas of the world that become warm during the summer. In areas that have harsh winters, ponds that are a minimum of 1.5 meters (4 1/2 feet) are most common. 

Koi's bright colors put them at a severe disadvantage against predators; a white-skinned Kohaku is a visual dinner bell against the dark green of a pond. Herons, kingfishers, raccoons, cats, foxes, and badgers are all capable of emptying a pond of its fish. A well-designed outdoor pond

  will have areas too deep for herons to stand in, overhangs high enough above the water that mammals can't reach in, and shade trees overhead to block the view of aerial passers-by. It may prove necessary to string nets or wires above the surface. A pond usually includes a pump and filtration system to keep the water clear. 

Koi aquarium cold water fish are an omnivorous fish and will often eat a wide variety of foods, including peas, lettuce, and watermelons. Koi food is designed not only to be nutritionally balanced, but also to float so as to encourage them to come to the surface. When they are eating, it is possible to check koi aquarium cold water fish for parasites and ulcers. Koi will recognize the person feeding them and gather around him or her at feeding times. They can be trained to take food from one's hand. In the winter, their digestive system slows nearly to a halt, and they eat very little, perhaps no more than nibbles of algae from the bottom. Their appetite will not come back until the water becomes warm in the spring. When the temperature drops below 50 degrees Fahrenheit (10 °C), feeding, particularly with protein, is halted or the food can go rancid in their stomach, causing sickness. If kept properly, koi can live about 30–40 years. Some have reportedly lived up to 200 years.

The Goldfish aquarium cold water fish is usually classified as a coldwater fish, and it can live in an unheated aquarium.

Goldfish may be coldwater fish, but this does not mean they can tolerate rapid changes in temperature. The sudden shift in temperature that comes at night, for example in an office building where a goldfish might be kept in a small office tank, could kill them, especially in winter. Temperatures under about 10 °C (50 °F) are dangerous to fancy varieties of goldfish, though commons and commets can be exposed to these temperatures without a problem. Extreme high temperatures (over 82°F) can start to become harmful to the fish, though can actually be benificial when fighting protozoan infestations, increasing the rapidity of the parasite's life-cycle, thus eliminating the problem more quickly. The optimum temperature seems to be around 75°F .

The popular image of a goldfish in a small fishbowl is an enduring one. However, some countries have banned the sale of bowls of that type under animal rights legislation due to the risk of stunting, deoxygenation and ammonia/nitrite poisoning in such a small environment.

Goldfish, like all fish that are kept as pets, do not like to be petted. In fact, touching a goldfish can be quite dangerous to its health, as it can cause the protective slime coat to be damaged or removed, which opens the fish’s skin up to infection from bacteria or parasites in the water.

Fancy goldfish are unlikely to survive for long in the wild as they are handicapped by their bright fin colors; however it is not beyond the bounds of possibility that such a fish, especially the more hardy varieties such as the Shubunkin, could survive long enough to breed with its wild cousins. Common and comet goldfish can survive, and even thrive, in any climate in which a pond for them can be created. Introduction of wild goldfish can cause problems for native species. Within three breeding generations, the vast majority of the goldfish spawn will have reverted to their natural olive color. Since they are carp, goldfish are also capable of breeding with certain other species of carp and creating hybrid species.

If left in the dark for a period of time, a goldfish will turn almost gray. Goldfish aquarium cold water fish have pigment production in response to light, which is almost like our tanning in the sun. Fish have cells called chromatophores that produce pigments which reflects light, and

Weather loach aquarium cold water fish are active, peaceful, and hardy fish that are sometimes used as starter fish in an aquarium. They can be "friendly" towards humans, allowing physical contact and hand feeding. They have, however, been known to attack very small fish in smaller aquariums. There are other varieties bred from captivity like the gold strain and the peppered strain(not to be confused with the pepper loach). 

The loaches will be more active given more space and greater numbers. Solitary weather loaches tend to spend much of their time hiding. They will spend a lot of time hiding or staying still, but should be given a place to stay which will have cover and shade. Tank decorations that they can swim through and driftwood both work great for this. Due to their jumping ability the average cover should be enhanced with tape or other barriers. However, if you happen to find your loach black and dry on the floor one morning, try placing it back in the aquarium. Usually it will revive and swim away and make a full recovery. Also, they may even travel up tubes and take up residence in filters, so check there if your dojo doesn't show up for roll call one day. 

Weather loach aquarium coldwater fish enjoy digging and burrowing themselves in the substrate of their tank, so make sure that your substrate is fine enough for them to dig in. If you keep live plants in your tank, they will be uprooted by the loaches, so it is a good idea to weight your plants. The weather loach is also peculiar in that it will sometimes bury itself in the substrate during times of stress. This often surprises new owners, as the fish will "disappear" shortly after introduction to the tank only to "reappear" later. Because of their appetite for snails, these loaches can help alleviate snail infestations in tropical fish tanks, though many have reported that while weather loaches do eat snails, they do not eat them at a fast enough rate to deal with an infestation. The cold water fish prefer a pH of 6.5-8.0 but will tolerate far more acidic conditions even for extended amounts of time with little negative reaction. This makes the Weather Loach a great choice for first-time aquariums and for those who want a fish tank but do not want the intense, daily attention other fish require. This fish should be kept in groups of at least 3, as they like to be in physical contact with each other and feel each other with their barbels when they rest.

The Nimbochromis polystigma aquarium cold water fish (Lake Malawi cichlid) is a relatively peaceful species, as long as its cohabitants are not small enough to be considered prey. It's an enthusiastic feeder, and will eat all of the usual foods given to cichlids, and has the rather endearing habit of leaping from the water to try to get at food or fingers. In aquaria it can grow to 30cm (12 inches), and requires a large aquarium - at least 300 litres - and can be kept with other haplochromines and most mbuna. It is best to have some rocks for them to hide in when threatened, but they also need room to swim.

The northern redbelly dace aquarium cold water fish, Phoxinus eos, is a freshwater cyprinid fish, generally found in lakes and small streams in the northeastern United States and eastern Canada. The fish can reach lengths of up to 5 cm (2 inches). The species hybridises freely with the closely related finescale dace, Phoxinus neogaeus.

The Pumpkinseed aquarium cold water fish (Lepomis gibbosus) is a freshwater fish of the sunfish family (Centrarchidae) of order Perciformes. It is native to northeastern North America, from New Brunswick to South Carolina but it has been introduced elsewhere in North America as well as throughout much of Europe where it is considered an invasive species. 

Pumpkinseed aquarium cold water fish reach a maximum length of about 40 cm (16 inches), although sizes of 15–20 cm (6–8 inches) are more typical. Weights are normally less than 450 grams (1 pound), although larger specimens can be encountered. The fish present an oval silhouette and are very compressed laterally; it is this body shape, resembling the seed of a pumpkin, which provides them with their common name. The coloration includes orange, green, yellow, or blue speckles on an olive back, yellow sides and a yellow to orange belly and breast. As with all centrarchids, they have sharp spines in the dorsal and anal fins. 

Pumpkinseed aquarium cold water fish prefer shallow water with some weed cover. They are often typical of ponds and small lakes, preferring water temperatures of 4–22 °C (39–72 °F). They are active during the day and rest near the bottom at night. These fish reproduce rapidly and are low on the food chain. They eat a variety of insects, including mosquito larvae, along with small molluscs and crustaceans. They also feed on smaller fish, including smaller pumpkinseeds. In the shallow areas of which they are typical, the fish exploit the entire water column from the bottom to surface. In turn, they provide food for birds and mammals (including humans). 

Sexual maturity occurs at age two. Males prepare nests in colonies on gravel bottoms in late spring. The males are territorial and chase even early-arriving females away. When a female reaches a nest, she is joined by the male, and eggs are deposited in a cloud of milt. The eggs settle and stick to the pebbles. The female departs as soon as the eggs have been deposited. Males may welcome several females over several days. The male guards the nest as the eggs hatch in a few days. The males continue to guard the offspring, herding them into a ball-like cloud. After a week or two, the young gain sufficient energy and maintaining the order of the cloud becomes impossible at which point the offspring disperse and the male departs the nest. 

Pumpkinseed aquarium cold water fish are known to interbreed with the closely-related bluegill, which they resemble in form and coloration. The pumpkinseed, like other sunfishes, is very popular with anglers. The fish is often the first one caught by young anglers. The fish is considered to be a fine food fish although it is less prized than the bluegill. Pumpkinseeds feed all day and can be caught with live bait or with small lures. They actively fight the line as they are reeled in. This species is regarded as a panfish due to its size and edibility. L. gibbosus is known by many other common names, including punky, pond perch, sun bass, crapet-soleil (in Québec), kivver or kivvie(New England), yellow sunfish, and simply sunfish (or "sunny"). The specific epithet, gibbosus, derives from the Latin gibb(er)osus (hunch backed).

The Rainbow Darter (Etheostoma caeruleum) is a native North American fish that can be found in small fast moving streams and small to medium-sized rivers. It grows to 2 inches (51 mm) to 3 inches (76 mm) in length.The Etheostoma caeruleum is very sensitive to pollution and silt, staying in clean pollution free water. Rainbow darters are easily identified by three dark spots on the back; also they have blue and orange in their dorsal and anal fins.

This pinkish fish (Rosy Barb) is one of the larger species of Barbs growing up to 6 inches (14 cm) in length. Their color becomes bolder during their mating periods. The male has a brighter pinkish color and the female is slightly plumper. In the wild their omnivorous diet consists of worms, insects, crustaceans, and plant matter. They have a lifespan of up to 5 years. Rosy Barbs natively live in lakes and fast flowing water in a subtropical climate. Their natural habitat has a pH of 6 to 8, a water hardness of 5-19 dGH, and a temperature range of 64–72 °F (18–22 °C).

The Southern Redbelly Dace aquarium cold water fish (Phoxinus erythrogaster), is a North American species of temperate freshwater fish belonging to the Phoxinus genus of the cyprinidae family. The natural geographic range extends from Western New York to Minnesota, and south to Oklahoma, Arkansas, and Alabama. This fish prefers flowing pools of creeks and streams. The Southern redbelly dace reaches a maximum length of about 9 cm.

The extremely similar Northern REdbelly Dace coldwater aquarium fish can be distinguished by a rounder, blunter head and a more upturned mouth, as well as by differences in spawning behavior.

The Gasterosteidae coldwater aquarium fish are a family of fish including the Sticklebacks. FishBase currently recognises sixteen species in the family, grouped in five genera. However several of the species have a number of recognised subspecies, and the taxonomy of the family is thought to be in need of revision. Although some authorities give the common name of the family as "sticklebacks and tube-snouts", the tube-snouts are currently classified in the related family Aulorhynchidae. 

The family includes the three-spined stickleback Gasterosteus aculeatus aculeatus, common in Northern Temperate Climates around the world including Europe, Alaska, and Japan and colloquially known in United Kingdom as the "tiddler", or "sprick". Niko Tinbergen's studies of the behaviour of this fish were important in the early development of ethology as an example of a fixed action pattern.

The Ticto Barb is an active schooling fish, which is usually kept in groups. When in large enough groups, they will not bother any other species of fish. They prefer a well planted environment that is similar to the still and shallow waters with mud bottoms of their native habitat. Ticto barbs are egg-layers that spawn among a course gravel bed. During spawning, they will lay approximately 150 eggs, laying around 20 at a time. Once spawning is finished, they will usually eat any of the eggs that they find. It is usually necessary to separate the fish from the eggs after spawning in order to prevent the eggs from being eaten. The eggs will hatch in approximately 1 day and will be free-swimming a day later.

Zebrafish coldwater aquarium fish are hardy fish and considered good for beginner aquarists. Their ease of keeping and breeding, beauty, price, playful nature and broad availability all contribute to their popularity. They thrive best at temperatures above 22 degrees Celsius (71.6 degrees Fahrenheit) and below 27 degrees Celsius (80.6 degrees Fahrenheit). They feed on worms and small crustaceans and on insect larvae. They also thrive as shoals of 6 or more, although they do interact well with other fish types in the Aquarium. However, they are susceptible to Oodinium, or Velvet disease, Microsporidia (Pseudoloma neurophilia), and mycobacterium species.

Transgenic coldwater aquarium zebrafish have become commercially available that express green fluorescent protein, red fluorescent protein, and yellow fluorescent protein. They are tradenamed GloFish. Other varieties include golden, sandy, longfin and leopard. The Leopard danio, previously known as Danio frankeri, is a spotted colour morph of the zebrafish Danio rerio caused by a pigment mutation. Xanthistic forms of both the zebra and leopard pattern, along with long-finned varieties have been obtained via selective breeding programs for the aquarium trade.