A bellows is provided for fluid storage and displacement used in precise fluid indication in a capillary tube. The bellows is made of a housing made of flexible, watertight material. The housing is made up of an upper portion, a lower portion, and an outer accordion formed portion. The accordion formed portion has a length/and is sealingly connected along a periphery between the upper and lower portions. At least one entry/exit port is formed on at least one of the portions thereof. At least one of the upper and lower portions extends from a periphery of the accordion formed portion substantially within the housing so as to reduce the storage volume.