Chapter XX.

1. Animals are not all in good health at the same season, nor in the same degrees of heat and cold. Their health and diseases are different at different seasons in various classes, and on the whole are not alike in all. Dry weather agrees with birds, both in respect of their general health and the rearing of their young, and especially with pigeons; and wet weather, with few exceptions, agrees with fish. On the contrary, showery weather generally disagrees with birds, and dry weather with fish; for, on the whole, abundance of drink does not agree with birds.

2. For the birds with crooked claws, generally speaking, as it was before remarked, do not drink. But Hesiod was ignorant of this circumstance; for in relating the siege of Nineveh he represents the presiding eagle of the augury drinking. Other birds drink, but not much; neither do any other oviparous animals with spongy lungs. The sickness of birds is manifest in their plumage; for it is uneven, and has not the same smoothness as when they are well.

3. The generality of fish, as it was observed, thrive the most in rainy years; for not only in such seasons do they obtain a greater supply of food, but the wet weather agrees with them as with the plants that grow on land; for potherbs, even if watered, do not grow so well as in wet weather. The same is the case with the reeds that grow in ponds; for they never grow, as we may say, except in rainy weather.

4. And this is the reason why so many fish migrate every summer into the Pontus; for the number of rivers which flow into it render the water fresh, and also bring down a supply of food, and many fish also ascend the rivers, and flourish in the rivers and lakes, as the amia and mullet. The cobii also become fat in the rivers; and on the whole, those places which have the largest lakes furnish the most excellent fish.

5. Of all kinds of water, summer showers agree best with fish; and if the spring, summer, and autumn have been wet, a fine winter. And to speak generally, if the season is healthy for mankind, it will be the same for fish. They do not thrive in cold places. Those which have a stone in their head, as the chromis, labrax, sciœna, and phagrus, suffer most in the winter; for the refrigeration of the stone causes them to freeze and be driven on shore.

6. Abundant rain confers health on most fish; but the contrary is the case with the mullet and cephalus, which some call marinus; for if there is a great supply of rain water, they soon become blind. The cephali are particularly liable to this disease in the winter; for their eyes become white. When captured they are lean, and at last perish altogether. They do not, however, appear to suffer so much from the wet as from the cold; for in other places, and especially in the swamps in the neighbourhood of the Argive Nauplia, many are found blind in severe weather, and many also are taken with white eyes.

7. The chrysophrys also suffers from the cold; the arachnas from the heat, which makes it lean. Dry seasons agree better with the coracinus than with any other fish, and for this reason, because it is generally warm in dry weather. Particular localities are favourable to different species, as either the neighbourhood of the land, or the deep waters to those which only frequent one of these localities, or particular places to those which frequent both. There are especial places in which each of them thrive; but, generally speaking, they prefer places full of sea weed; for those which inhabit places with plenty of food are generally found to be fatter; for those that eat fuci obtain plenty of food, while those that are carnivorous find an abundant supply of fish.

8. They are also affected by northern and southern aspects, for the long fish thrive best in northern situations, and in northern places in the summer time more long fish than flat fish are taken in the same locality. The tunny and xiphia suffer from the œstrus, at the rising of the dog-star, for both these fish at this season have beneath their fins a little worm which is called œstrus, which resembles a scorpion, and is about the size of a spider; they suffer so much from this torment that the xiphias leaps out of the sea as high as the dolphin, and in this manner frequently falls upon ships.

9. The tunny delights in warm weather more than any other fish, and they resort to the sand near the sea-shore for the sake of the warmth, and there they float on the surface; the small fish are safe because they are overlooked, for large fish pursue those of a moderate size. The greater portion of the ova and melt are destroyed ... by the heat, for whatever they touch they entirely destroy.

10. The greatest number of fish are taken before sunrise and after sunset, or just about sunrise and sunset, for the casts made at this period are called seasonable. For this reason the fishermen take up their nets at this time, for the sight of the fish is then most readily deceived. During the night they remain quiet, and at mid-day, when the light is strong, they see very well.

11. Fish do not appear to be subject to any of those pestilential diseases which so often occur among men and quadrupeds, as the horse and ox, and other animals, both domestic and wild. They appear, however, to suffer from ill health, and the fishermen consider that this is proved by the capture of some lean, and apparently weak individuals, and others that have lost their colour, among a number of fat ones of the same kind. This is the nature of sea-fish.

12. No pestilential disease attacks river and pond fish, though some of them are subject to peculiar diseases, as the glanis, from its swimming near the surface, appears to be star-struck by the dog-star, and it is stupefied by loud thunder. The carp suffers in the same way, but not so severely. The glanis, in shallow water, is often destroyed by the dragon-serpent. In the ballerus and tilon a worm is produced, under the influence of the dog-star, which makes them rise to the surface and become weak, and when they come to the surface they are killed by the heat; a violent disease attacks the chalcis, which is destroyed by a number of lice, which are produced under its gills; no other fish appear to be subject to such a disease.

13. Fishes are poisoned with the plant called mullein, for which reason some persons capture them by poisoning the waters of rivers and ponds; and the Phœnicians poison the sea in the same way. There are two other plans which are adopted for the capture of fish; for since fish avoid the deep parts of rivers in cold weather (for even otherwise the river water is cold), they dig a ditch through the land to the river, which they cover over with grass and stones so as to resemble a cave, with one opening from the river, and when the frost comes on they capture the fish with a basket. The other mode of fishing is practised both in summer and winter. In the middle of the stream they raise a structure with faggots and stones, leaving one part open for a mouth; in this a basket is placed, with which they catch the fish, as they take away the stones.

14. Rainy years agree with all the testacea except the purpura; this is a proof of it, if placed near the mouth of a river, they take the fresh water, and die the same day. The purpura will live about fifty days after it has been taken. They are nourished by each other, for a plant like a fucus or moss grows upon their shells. They say that whatever is cast to them for food is done for the sake of weight, that they may weigh the more.

15. Dry weather is injurious to other testacea, for it renders them fewer in quantity and inferior in quality, and the pectens become more red. In the Pyrrhæan Euripus the pectens perish, not only from the instrument with which the fishermen scrape them together, but also from dry weather. The other testacea thrive in wet weather, because it makes the sea-water fresher. The cold of the Pontus and of the rivers that flow into it renders bivalve shells rare. The univalves, however, are frozen in cold weather. This is the nature of aquatic animals.