Sources : Pike

Pliny the Elder [1st century CE] (Natural History, Book 9, 17): The tuna is of exceptional size; we are told of a specimen weighing a third of a ton and having a tail 3 ft. 4 in. broad. Fish of no less size also occur in certain rivers, the catfish in the Nile, the pike (isox) in the Rhine, the sturgeon in the Po, a fish that grows so fat from sloth that it sometimes reaches a thousand pounds; it is caught with a hook on a chain and only drawn out of the water by teams of oxen. And this monster is killed by the bite of a very small fish called the anchovy which goes for a particular vein in its throat with remarkable voracity. - [Rackham translation]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 6:24): The pike [lupus or sea-wolf], as has been said, is named for its voracity. It is a difficult fish to catch; it is said that when a pike is surrounded by a net, it digs into the sand with its tail, and, hidden in this way, slips by the net. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Fish 7.34; 7.50): [Thomas describes the pike under the names ezox and lucius piscis.] [Fish 7.34] The pike (ezox) is the largest fish of the Danube, which the Swedes call husem. This fish is light throughout its whole body, and has nothing rough in its body or in its behavior, but it is a very gentle and timid animal, since it cannot defend itself even from the smallest fish. Hence it is driven to flight by a stinging little fish. [Here Thomas has confused Pliny the Elder'saccount of the sturgeon with the pike, which Pliny mentions in the same chapter; see the Pliny quote above.] This fish most willingly associates with the sturgeon; which the pike, as soon as he sees, flees to the hiding-places which it is wont to dig for himself on the shores; but sometimes in vain, because an aggressive sturgeon drives out the one who is hiding. The pike fleeing then follows the sturgeon, and since both are large and cannot hide even in the strongest waters by running and stirring the waters before them, together they are caught by the fishermen. This fish when caught may be preserved with strong wine or milk, and this is because when it has been preserved with much wine, it can be kept for many days, and this in order that the grace of food may be carried to remote lands. It is so large that it can hardly be drawn by a team of three or four horses [a confusion with Pliny's account of the sturgeon]. Its meat is very sweet and very similar in taste and appearance to pork. The pike has one intestine, and the bones are few and small, and those are cartilaginous rather than solid. But in its head it has many solid bones. And in this are noted those who are great in the affections of the heart in the purpose of virtue, but are lacking in the effect of action. [Fish 7.50] The pike [lucius piscis], as he says [i.e. Liber rerum], is a fish which is also called a sea wolf. If it has fresh river water and sufficient food for life, it can achieve its greatest size through the seasons. Its food is fish and anything that crawls in the manner of frogs. It can devour a fish nearly its own size. For when it has subdued its victim, it first devours the head with his mouth, after which it proceeds gradually to the next part of the body, until it consumes the whole. It does not spare its own kind, either because of natural cruelty or because it is envious of their food and cannot stand their robbery. It also pursues its own offspring, where they have taken the form of fish. It carries a crystal-like stone in its head, but this only when it is old. [Thomas took what follows from a different source, and so repeated some of the description.] The pike are impregnated, as Aristotle says, by the wind blowing from the north and so are the fishes that escape at length. It is less effective in the darkness of the depths. The pregnant female goes up the waters as far as she can from the place where she is accustomed to dwell, and lays her eggs there, so that her children may not be a hindrance to her, and this because of her natural cruelty, because she is jealous of their food and cannot stand their robbery. Others have said that she goes up the waters to find fresher water, because water is always sweeter the closer it is to a spring. It has sharp scales and fins. If a sea wolf is seized it by the head, it can be quickly swallowed; if, however, it is seized from the tail, it is absolutely impossible to swallow, because the scales are rough in the opposite direction. - [Badke translation/paraphrase]