The Collaborative International Dictionary
Gibel \Gib"el\, n. [G. gibel, giebel.] (Zo["o]l.) A kind of carp ( Cyprinus gibelio); -- called also Prussian carp.
Prussian \Prus"sian\, a. [From Prussia, the country: cf. F. prussien.] Of or pertaining to Prussia. -- n. A native or inhabitant of Prussia.
Prussian blue (Chem.), any one of several complex double cyanides of ferrous and ferric iron; specifically, a dark blue amorphous substance having a coppery luster, obtained by adding a solution of potassium ferrocyanide (yellow prussiate of potash) to a ferric salt. It is used in dyeing, in ink, etc. Called also Williamson's blue, insoluble Prussian blue, Berlin blue, etc.
Prussian carp (Zo["o]l.) See Gibel.
Prussian green. (Chem.) Same as Berlin green, under Berlin.
Wikipedia
The Prussian carp, silver Prussian carp or Gibel carp (Carassius gibelio, sometimes Carassius gibelio gibelio and, before 2003, Carassius auratus gibelio), is a member of the family Cyprinidae, which includes many other fish, such as the common carp, and the smaller minnows. It is a medium-sized cyprinid, and does not exceed a weight of 6.6 pounds (3 kg) and a size of 45 cm. They are usually silver, although other color variations exist. They are omnivorous and feed on plankton, invertebrates, plant material and detritus. Originally from Asia (Siberia), they have been introduced to and are now inhabiting lakes, ponds, and slow-moving rivers throughout Europe, North America, and Asia.