Gas turbine arrangement for at least dual fuel operation, comprising - a compressor; - at least one combustor, preferably a plurality of combustors; - a plurality of fuel manifolds (21,22,23), each connected to each of the at least one combustor; - a control system; wherein a first manifold of the plurality of fuel manifolds (21,22,23) is configured to deliver either a, preferably gaseous, first fuel or a compressor bleed fluid, the first manifold being connectable to a bleed port of the compressor via a bleed valve for delivering the compressor bleed fluid, wherein the first manifold is connected to at least one first passage of the at least one combustor for ejecting the first fuel or the compressor bleed fluid into a combustor space; a second manifold of the plurality of fuel manifolds (21,22,23) is configured to deliver at least a, preferably gaseous, second fuel, wherein the second manifold is connected to at least one second passage of the at least one combustor for ejecting the second fuel into the combustor space; the control system, when the combustor is operated solely with the second fuel, is configured - to provide the second fuel to the second manifold and to continuously open the bleed valve to provide compressor bleed fluid into the first manifold such that the first fuel in the first manifold is replaced by the compressor bleed fluid, - to monitor a flame behaviour and/or fuel distribution in the combustor space, and - to modify the flame behaviour and/or fuel distribution by controlling of the bleed valve over time by throttling a mass flow of the compressor bleed fluid provided to the at least one first passage or alternatively by increasing a mass flow of the compressor bleed fluid provided to the at least one first passage to adapt to fuel properties of the second fuel. - to control additionally a manifold individual further bleed valve over time by throttling or alternatively increasing a mass flow of the compressor bleed fluid provided to the at least one first passage. - a compressor; - at least one combustor, preferably a plurality of combustors; - a plurality of fuel manifolds (21,22,23), each connected to each of the at least one combustor; - a control system; wherein a first manifold of the plurality of fuel manifolds (21,22,23) is configured to deliver either a, preferably gaseous, first fuel or a compressor bleed fluid, the first manifold being connectable to a bleed port of the compressor via a bleed valve for delivering the compressor bleed fluid, wherein the first manifold is connected to at least one first passage of the at least one combustor for ejecting the first fuel or the compressor bleed fluid into a combustor space; a second manifold of the plurality of fuel manifolds (21,22,23) is configured to deliver at least a, preferably gaseous, second fuel, wherein the second manifold is connected to at least one second passage of the at least one combustor for ejecting the second fuel into the combustor space; the control system, when the combustor is operated solely with the second fuel, is configured - to provide the second fuel to the second manifold and to continuously open the bleed valve to provide compressor bleed fluid into the first manifold such that the first fuel in the first manifold is replaced by the compressor bleed fluid, - to monitor a flame behaviour and/or fuel distribution in the combustor space, and a first manifold of the plurality of fuel manifolds (21,22,23) is configured to deliver either a, preferably gaseous, first fuel or a compressor bleed fluid, the first manifold being connectable to a bleed port of the compressor via a bleed valve for delivering the compressor bleed fluid, wherein the first manifold is connected to at least one first passage of the at least one combustor for ejecting the first fuel or the compressor bleed fluid into a combustor space; a second manifold of the plurality of fuel manifolds (21,22,23) is configured to deliver at least a, preferably gaseous, second fuel, wherein the second manifold is connected to at least one second passage of the at least one combustor for ejecting the second fuel into the combustor space; the control system, when the combustor is operated solely with the second fuel, is configured - to provide the second fuel to the second manifold and to continuously open the bleed valve to provide compressor bleed fluid into the first manifold such that the first fuel in the first manifold is replaced by the compressor bleed fluid, - to monitor a flame behaviour and/or fuel distribution in the combustor space, and - to provide the second fuel to the second manifold and to continuously open the bleed valve to provide compressor bleed fluid into the first manifold such that the first fuel in the first manifold is replaced by the compressor bleed fluid, - to monitor a flame behaviour and/or fuel distribution in the combustor space, and - to modify the flame behaviour and/or fuel distribution by controlling of the bleed valve over time by throttling a mass flow of the compressor bleed fluid provided to the at least one first passage or alternatively by increasing a mass flow of the compressor bleed fluid provided to the at least one first passage to adapt to fuel properties of the second fuel. - to control additionally a manifold individual further bleed valve over time by throttling or alternatively increasing a mass flow of the compressor bleed fluid provided to the at least one first passage.