The bioelectrical impedance physical device is described here. All models are equipped with a 4-electrode compression stainless steel array’s that are salt-water and corrosion proof. The array consists of two signal electrodes and two detecting electrodes that introduce an 800μA, 50kHz, AC current that is capable of voltage changes between 3.75-10.60V. When the 4-electrode array touches fish, the outside signal electrodes introduce the current and the inside two measure it. A 4-electrode array is used as they help the applied current approximate parallel field lines within the fish, negate skin electrode interfaces, and approximate a cylindrical shape. From this, the two electrical measures that are vectors of the current, are sensitive to changes in the cellular and interstitial volumes of the tissue, and are representative of the impedance of flow. .