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also to take into account the difference of the seas as well as of the shores, in 

 order that fish brought from foreign places may not disappoint us ; for every fish 

 cannot live in every sea, as for instance the helops which is nourished only in the 

 Pampliylian sea, the dory (faber), accounted as one of the best fish in our muni- 

 cipality of Gades, and vifhich acconling- to old custom is called zeus; the scarus, 

 which is most abumlant on all the shores of Asia Minor and Greece as far as 

 Sicily, hut never swims out to the Spanish sea. Therefore if they are caught 

 and brought to our vivaria, they cannot be kept long. Of the valuable kinds, 

 the mwcena alone, although indij,'enous in the Tartesian sea and in the Carpa- 

 thian sea, which is its most distant h'ibitat, is able to live in any sea. But let us 

 now discourse about the site of fish-ponds." — Columella viii., 16. 



"We judge a pond to be far the best vvhich is so situated that each following 

 wave of the sea removes the one before it, and does not suffer the old one to remain 

 within the enclosure ; for this is very similar to the sea which is constantly ai^itat- 

 ed by the wind and is unable to become warm, since the cold sea rolls up from 

 the depth the cold wave to the upper portion. A pond is either cut out of a rock 

 — but there is very seldom a favourable opportunity for this, — or is constructed 

 on the shore by means of masonry. But in whatever way it is made it ought to 

 have a hollow cavity near the bottom, if it is always to be cold with the influx of 

 the rushing water ; some cavities should be simple and straight whither the scaly 

 shoal may retire, others should be bent in the form of a snail-shell, sufficiently 

 capacious, in which the murenae may take shelter, although some persons do not 

 like to mix these fish with others ot a different kind, because if they are harass 

 ed with rabies sinular to that which occur in dogs, they savagely persecute the 

 fishy shoals and kill many by biting them. Passages should be made on every 

 side of the piscina, if the nature of the place permit it, for thus the old water is 

 more easily removed, when an exit for the water is open opposite to its entrance. 

 These passages we think should be made near the bottom of the enclosure, if the 

 situation of the place allow it, so that the plummet line placed in the bottom of 

 the piscina should show a depth of seven feet of water above ; for this measure- 

 ment for the fishes of the pond is quite sufficient ; and there can be no doubt 

 that the more the water comes from the bottom of the sea, so much the colder it 

 is ; a condition which is most suitable for the swimming fishes. But if the spot 

 which we have thought suitable for a vivarium is on a level with the water of the 

 sea, the piscina is to be dug out to a depth of nine feet, and within two feet 

 from the top streams of water are to be brought by channels, and care must be 

 taken that these streams come in very copiously, since the quantity of water (in 

 the pond) which lies below the level of the sea, is driven out just as if a fresh 

 rush of sea-water had gained admittance. Many people are of opinion that, in 

 ponds of the nature just mentioned, long and tortuous recesses should be made 

 for the fishes in the sides of the cavity, as dark retreats for them. But if fresh 

 sea water is not continually running through the pond ; to do this is injurious ; 

 for reservoirs of this kind do not readily admit fresh supplies of water, and with 

 difficulty get rid of the old ; and stinking water is more injurious than darkness 

 is beneficial. Nevertheless, little holes should be hollowed out of the walls to 



