en-us /modules.php?name=News&file=article&sid=22 The bleeding heart tetra is a hardy, peaceful, schooling species that should be kept in groups of six or more. It does extremely well when kept with other peaceful fishes, such as Megalamphodus, Corydoras and Nannostomus species. /modules.php?name=News&file=article&sid=21 The kuhli loach ("coolie" is an often seen mistake) is a fascinating and hardy species that fits well into a small fish community aquarium. They like clean, clear water, and do best with aquarium gravel, such as fine sand, that does not have sharp edges. This approximately duplicates their natural habitat, which is the sandy beds of mountain streams or slow flowing rivers. They actually seem to do better in an aquarium that has a slight buildup of organic mulm or peat moss on the surface of the substrate. /modules.php?name=News&file=article&sid=20 Paradise fish can be kept with other paradise fish as juveniles, as well as with other similar-size community tankmates with the same temperature requirements. However, as they mature, males will engage in fierce battles, so only one male should be kept per aquarium. /modules.php?name=News&file=article&sid=19 The clown loach is an active schooling fish that is best kept in small groups (three to six fish). It will tolerate tankmates of other species, although docile species may become agitated by the constant activity of this fish. /modules.php?name=News&file=article&sid=18 In the wild, most Corydoras swim in schools of several dozen or more, and similar conditions should be duplicated in the home aquarium. Corydoras aeneus should be kept in groups of six or more with other community tank fishes, such as small characins, livebearers and rasboras. /modules.php?name=News&file=article&sid=17 The glass catfish is one of the most unusual fish commonly kept in the hobby, and it is certainly the most transparent. All of the bones and the sac that holds the internal organs are clearly visible through the transparent flesh of the glass catfish. Fortunately, glass cats are delicate enough that they cannot be abused by being dyed different colors as has been done with the common glass fish. /modules.php?name=News&file=article&sid=16 Tropheus are often territorial and may be intolerant of members of their own species. However, they seldom harass other tankmates. /modules.php?name=News&file=article&sid=15 This robust representative of the subgenus Theraps can grow to 12 inches in length. It is native to the basin of the Rio Usumacinta in southeastern Mexico and northern Guatemala and to coastal rivers in neighboring Belize. Like most Theraps, this species is slow-growing and requires several years to develop its full color pattern. /modules.php?name=News&file=article&sid=14 The marbled hatchetfish found in the local fish store are all caught in the wild — they have been spawned, but not on a commercial basis. Also, there are at least two species, and probably some others, that come in under the common name of marbled hatchetfish. /modules.php?name=News&file=article&sid=13 The neon tetra was the first wild-caught fish that really set the tropical fish hobby into a dither, and contributed much to establishing the "tropical" fish hobby. When neons were first introduced in Europe and then America, they commanded incredibly steep prices. Now that they are produced in huge quantities in the Far East they are a common staple and always available.