Velvet Red Swordtails are TROPICAL FRESH WATER FISH (Xiphophorus hellerii in family Poeciliidae of order Cyprinodontiformes). A live-bearer, it is closely related to the southern platyfish or "platy" (X. maculatus) and can interbreed with it. It is native to an area of North and Central America stretching from Veracruz, Mexico, to northwestern Honduras.
Show Guppies are a FRESH WATER TROPICAL FISH. They only differ from regular guppies by being more colorful, beautiful, larger, more healthy and with more elaborate fin structures and cosmetic traits -- due to the careful intervention of humans. No chemicals or other harmful elements are used in producing show guppies. (Poecilia reticulata), also known as the millionfish, is one of the most popular freshwater aquarium fish species in the world. It is a small member of the Poeciliidae family (females 46 centimeters (1.62.4 in) long, males 2.53.5 centimeters (1.01.4 in) long) and like all other members of the family, is live-bearing. Guppies are native to Antigua and Barbuda, Barbados, Brazil, East Timor, Guyana, Mayotte, Netherlands Antilles, Trinidad and Tobago, the U.S. Virgin Islands, Venezuela, and Vietnam. However, guppies have been introduced to many different countries on all continents, except Antarctica. Sometimes this has occurred accidentally, but most often as a means of mosquito control, the hope being that the guppies would eat the mosquito larvae slowing down the spread of malaria.
Plecostomus (Algae Eaters)
Hypostomus Plecostomus is the scientific name for a type of FRESH WATER TROPICAL FISH from Central and South America, belonging to the family Loricariidae. They are large algae eaters, and to differentiate them from small algae eaters, they are often referred to as plecostomus, often abbreviated as plecos or plecs. They are extremely popular in aquaria for their ability to clean tanks by eating algae growth. In Malaysia, these fish are called 'ikan bandaraya' or 'municipal fish' in English because of their ability to clean fish tanks. These friendly-natured fish can typically be purchased when about 8 cm (3 inches) and may grow up to (and in excess of) 60 cm (2 ft) if there is adequate room. We have personally seen some that were 3 feet long! :)
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https://www.youtube.com/watch?v=ycQbdcf55Kw