A procedure for measuring the transfer coefficient KLa for the removal rate of carbon dioxide by aeration devices in fish tanks was developed in the National Center for Mariculture in Eilat, Israel. The KLa for a paddlewheel and a submerged aerator were calculated, following experi- ments in which the aeration devices were used simultaneously for both carbon dioxide stripping and oxygenation. The paddlewheel was more efficient, with a transfer rate up to 1,200 g CO2 per hour and a stripping efficiency of 1.2 kg CO2 per kWh. In intensive sea bream culture, the cal- culated maximum feed load that a single paddlewheel aerator can support is 43.6 kg feed per day with an energy requirement of about 1.0 kWh per kg fish produced.