Selasa, 28 Juni 2011

ikan hiu

Hiu atau cucut adalah sekelompok (superordo Selachimorpha) ikan dengan kerangka tulang rawan yang lengkap [1] dan tubuh yang ramping. Mereka bernapas dengan menggunakan lima liang insang (kadang-kadang enam atau tujuh, tergantung pada spesiesnya) di samping, atau dimulai sedikit di belakang, kepalanya.

Hiu mencakup spesies yang berukuran sebesar telapak tangan hiu pigmi, Euprotomicrus bispinatus, sebuah spesies dari laut dalam yang panjangnya hanya 22 cm, hingga hiu paus, Rhincodon typus, ikan terbesar, yang bertumbuh hingga sekitar 12 meter dan yang, seperti ikan pausHiu banteng,
 
Carcharhinus leucas, adalah yang paling terkenal dari beberapa spesies yang berenang di air laut maupun air tawar (jenis ini ditemukan di Danau Nikaragua, di Amerika Tengah) dan di delta-delta.

ikan guppy

The guppy (Poecilia reticulata), also known as the millionfish,[1] is one of the most popular freshwater aquarium fish species in the world. It is a small member of the Poeciliidae family (females 4–6 centimetres (1.6–2.4 in) long, males 2.5–3.5 centimetres (1.0–1.4 in) long) and like all other members of the family, is live-bearing.

Taxonomy

Robert John Lechmere Guppy discovered this tiny fish in Trinidad in 1866, and the fish was named Girardinus guppii in his honour by Albert Günther later that year. However, the fish had previously been described in America. Although Girardinus guppii is now considered a junior synonym of Poecilia reticulata, the common name "guppy" still remains.
Over time guppies have been given a variety of taxonomic names, although Poecilia reticulata is the name currently considered to be valid.[2]

Distribution

Guppies are native to Antigua and Barbuda, Barbados, Brazil, Guyana, Netherlands Antilles, Trinidad and Tobago, the U.S. Virgin Islands and Venezuela.[3][4]
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. In many cases, these guppies have had a negative impact on native fish faunas.[5]