Fresh-water Fishes.—Of the fresh-water fish, which inhabit the rivers and tanks, so very little has hitherto been known to naturalists[3354], that of nineteen drawings sent home by Major Skinner in 1852, although specimens of well-known genera, Colonel Hamilton Smith pronounced nearly the whole to be new and undescribed species.
Of eight of these, which were from the Mahawelliganga, and caught in the vicinity of Kandy, five were carps; two were Leucisci, and one a Mastacembelus (M. armatus, Lacep); one was an Ophiocephalus, and one a Polyacanthus, with no serræ on the gills. Six were from the Kalanyganga, close to Colombo, of which two were Helostoma, in shape approaching the Chætodon; two Ophiocephali, one a Silurus, and one an Anabas, but the gills were without denticulation. From the still water of the lake, close to the walls of Colombo, there were two species of Eleotris, one Silurus with barbels, and two Malacopterygians, which appear to be Bagri.
The fresh-water Perches of Europe and of the North of America are represented in Ceylon and India by several genera, which bear to them a great external similarity (Lates, Therapon). They have the same habits as their European allies, and their flesh is considered equally wholesome, but they appear to enter salt-water, or at least brackish water, more freely. It is, however, in their internal organisation that they differ most from the perches of Europe; their skeletons are composed of fewer vertebræ, and the air bladder of the Therapon is divided into two portions, as in the carps. Four species at least of this genus inhabit the lakes and rivers of Ceylon, and one of them, of which a figure is given above, has been but imperfectly described in any ichthyological work[3371]; it attains to the length of seven inches.
In addition to marine eels, in which the Indian coasts abound, Ceylon has some true fresh-water eels, which never enter the sea. These are known to the natives under the name of Theliya, and to naturalists by that of Mastacembelus. They have sometimes in ichthyological systems been referred to the Scombridæ and other marine families, from the circumstance that the dorsal fin anteriorly is composed of spines. But, in addition to the general shape of the body, their affinity to the eel is attested, by their confluent fins, by the absence of ventral fins, by the structure of the mouth and its dentition, by the apparatus of the gills, which opens with an inferior slit, and above all by the formation of the skeleton itself.[3381]
Their skin is covered with minute scales, coated by a slimy exudation, and the upper jaw is produced into a soft tripartite tentacle, with which they are enabled to feel for their prey in the mud. They are very tenacious of life, and belong, without doubt, to those fishes which in Ceylon descend during the drought into the muddy soil.[3382] Their flesh very much resembles that of the eel; and is highly esteemed.[3383] They were first made known to European naturalists by Russell[3384], who brought to Europe from the rivers round Aleppo specimens, some of which are still preserved in the collection of the British Museum. Aleppo is the most western point of their geographical range, the group being mainly confined to the East-Indian continent and its islands.
In Ceylon only one species appears to occur, the Mastacembelus armatus.[3391] The back is armed with from thirty-five to thirty-nine short, stout spines; there being three others before the anal fin. The ground colour of the fish is brown, and the head has two rather irregular longitudinal black bands; deep-brown spots run along the back as well as along the dorsal and anal fins; and the sides are ornamented with irregular and reticulated brown lines. This eel attains to the length of two feet. The old females do not show any markings, being of a uniform brown colour.
In the collection of Major Skinner, before alluded to, brought together without premeditation, the naturalist will be struck by the preponderance of those genera which are adapted by nature to endure, a temporary privation of moisture; and this, taken in connection with the vicissitudes affecting the waters they inhabit, exhibits a surprising illustration of the wisdom of the Creator in adapting the organisation of his creatures to the peculiar circumstances under which they are destined to exist.
So abundant are fish in all parts of the island, that Knox says, not the running streams alone, but the reservoirs and ponds, "nay, every ditch and little plash of water but ankle deep hath fish in it."[3392] But many of these reservoirs and tanks are, twice in each year, liable to be evaporated to dryness till the mud of the bottom is converted into dust, and the clay cleft by the heat into gaping apertures; yet within a very few days after the change of the monsoon, the natives are busily engaged in fishing in those very spots and in the hollows contiguous to them, although the latter are entirely unconnected with any pool or running streams. Here they fish in the same way which Knox described nearly 200 years ago, with a funnel-shaped basket, open at bottom and top, "which," as he says, "they jibb down, and the end sticks in the mud, which often happens upon a fish; which, when they feel beating itself against the sides, they put in their hands and take it out, and reive a ratan through their gills, and so let them drag after them."[3401]