The collection is the first task in a long line of tasks all essential in an extended and contiguous chain of processes whereby the fish eventually arrive at a pet shop overseas.
The divers do not use aqualungs - they use a simple "hookah" arrangement, which consists of a small petrol engine driving an oil-less compressor feeding compressed air into a reserve air tank. From the tank two-outlet hoses 150 feet long terminate in diver's chest/back harnesses with a standard aqualung second stage regulator furnishing the air to the diver. Normally two divers are "down" at one time - each assisting the other - and the air hose doubles as a safety line in an emergency.
The fish are caught in fine-meshed nets – ten meters long and two meters deep – and local divers develop a definite skill in handling the nets at depths of up to twenty-five meters over the rocky lakebed. It is necessary to decompress the fish (no question of whistling them up directly from 25 meters to the surface!) and to achieve this they are caught by hand in the long net by the divers and placed in 50 liter plastic blue drums with mesh netting over the drums orifice. The drums are then progressively raised in stages for the next day or so. In collecting, both male and female fish are needed since Malawian fish are usually sold in pairs.
The divers will "work" several sites leaving the drums on a chain and float. After all the fish have been caught and decompressed, they are brought on board the dive boat - with non-stop water changing being the rule till arrival at the appropriate holding station.