In order to develop a system that could provide fish farmers with information to monitor stock performance and plan for a timely production, a computerised recording system was designed and tested on a trout hatchery in Scotland. It facilitated routine data capture on site with a small hand-held computer, programmed in BASIC language, which subsequently downloaded the data to a central desk-top microcomputer for further processing. Both direct and long-distance transmission via the telephone network using modems were possible. The LOTUS 1-2-3 general purpose software package, running on the microcomputer, was customised using 'macro' commands to accept the transmitted data and create files for storage on 'floppy' or 'hard' magnetic disks. Further information could be calculated and graphs and summary reports for stock control could be generated at will. Other customised LOTUS worksheets were developed to allow identification and access of specific historical data in order to calibrate regression equations and provide growth predictions for particular fish types. This information combined with cost and pricing details was further utilised by a linear programming package. Guidelines on optimum policies were formulated and sensitivity analyses could be performed. This production information system was implemented on the IBM-PC and the OLIVETTI M24 desk-top microcomputers and as field devices the SHARP PC 1500A and the HUSKY HUNTER were used. Since existing technology and 'off-the-shelf' software were utilised, the developed information system can be easily adjusted to suit the individual needs of different fish farms. However, the most important requirement for successful implementation would be the commitment and enthusiasm of the fish farm manager.