Fluid tanks for providing a print fluid to a printhead. In one embodiment, the fluid tank includes a first reservoir configured to contain a print fluid, and a second reservoir configured to contain the print fluid. The fluid tank further includes a first Input/Output (I/O) port configured to fluidly couple with a printhead to allow the print fluid to flow into or out of the first reservoir, and a second I/O port configured to fluidly couple with the printhead to allow the print fluid to flow into or out of the second reservoir. The fluid tank further includes a flexible membrane between the first reservoir and the second reservoir configured to flex to create a pressure difference between the first reservoir and the second reservoir.