Introduction
A goldfish is placed in a flow chamber,
filled with oxygen saturated water. New water, also saturated with oxygen,
flows into the chamber and an equivalent amount flows out, determined by the
flow rate. The goldfish in the chamber respire and take up oxygen from the
water. Unit of time is hours, and the concentration in cc/L.
Inflow water: The concentration of oxygen in the inflow-water depends on the temperature due to the solubility of oxygen (Gordon and Garcia 1989).
Respiration: The amount of oxygen respired by the fish depends on the mass of the fish and the weight specific respiration rate. The weight specific respiration rate is temperature dependent (Ege and Krog (1914) in Fry and Hart (1948). When the oxygen level fall below a threshold respiration become linearly dependent on oxygen concentration Fry and Hart (1948).
Results: The oxygen concentration in the tank starts at 6.36 cc/L and decreases. The decrease is fastest in the beginning, but gets less and less step until the concentration reaches equilibrium at 4.70 after 24-36 hour.