86 



MADRAS FISHERIES BULLETIN 



VOL. XIV, 



settle down on the bottom, resting lightly on their fins, just like 

 any ordinary person as Brer Ribbit would say. Other fish in the 

 aquarium do the same, particularly the heavily built ones; the Dog- 

 fishes among others do so and they even close their eyelids. Others 

 do not rest on the bottom, but remain merely motionless suspended 

 in the water. Many again never seem to sleep, the sardines and 

 their kin for example ; these fish are particularly difficult to keep 

 alive in a tank as they continue to swim about after dark and 

 receive such injuries by butting against the walls that they 

 invariably die within a few days or even hours. Only if a light be 

 kept burning throughout the night can they be protected from 

 injuring themselves. 



Fig. 19. — Velamin [Lethriniis nehnlosus). X ^■ 



The Serranid sea-perches are among our most abundant and 

 valuable food-fishes. Many species are found in our seas, varying 

 enormously in colour and size. The former characteristic renders 

 their scientific identification peculiarly difficult. 



One of the larger and most numerous of these sea-perches is 

 the Kalawa of the Tinnevelly coast, a Bsh not unlike the cod in 

 outline and not infrequently called the Indian Rock Cod. It 

 abounds on the hard bottom that stretches from the southern 

 extremity of India to the lOO-fathom line, and with other sea-per- 

 ches of the genera Lutiaiiiis and Lcthriuus may one day be 

 brought to m:irket by the tens of thousands when steam-trawling 

 is begun on the rich fishing grounds off Cape Comorin. 



