NOVELTY - Production (M1) of methane for use as a renewable energy source, comprises using sludge and waste water from the fish industry by combining the apparatus shown in the figure in the specification, with pisciculture apparatus to provide a self-contained, integrated system.    USE - The methane produced by M1 is useful to generate electricity via the production of steam or directly fed into electricity generators.    ADVANTAGE - Methane is a renewable and cheap energy source and by using M1 can be produced from organic waste from fish farming. Producing methane by M1 reduces the amount of carbon dioxide produced by classic fermentation of organic waste from 35% to 11.66%, making the process more environmentally sound both for pollution of ground water and for the destruction of the ozone layer. By using a fluid to cool the reaction chambers, a lower temperature can be sustained without diluting the hot gas; oil is less subject to pressure than air would be. Previous methods have used air as a coolant but this has caused a reduction in the turbine temperature since the air mixes with the hot gas. The sludge by-product of M1 can be used to produce fertilizer with a high nitrogen content. M1 does not produce such nasty odors as prior methods.    DETAILED DESCRIPTION - M1 apparatus comprises an outlet pipe from a fish tank leading via a heating chamber comprising a burner fuelled by methane, to a fermentation vat. The fermentation vat comprises a mixer and two outlet pipes, one leading to a reservoir for recuperating waste water, and the other leading to a methane storage drum. The methane storage drum has a pipe leading either to an electric group or to the burner. Heating water is circulated back to the fish tank where it is maintained at 15-16 degreesC.    DESCRIPTION OF DRAWING(S) - waste water reservoir (1)    fermentation vat (4)    mixer (5)    system of heating pipes (6)    outlet pipe for methane (7)    heating chamber (9)    methane storage drum (11)    methane powered burner (12)    methane outlet pipe (16)    compressor (17)    electric group (19)    water temperature maintenance system (22)    fish tank (23)    waste water outlet pipe (24)