Abstract: The present work aims at finding an optimized finite difference scheme for the solution of problems involving pure convection heat transfer in slab shaped fresh water fish pieces. A generalized mathematical model was written in dimensionless form and an optimized scheme of solutions was worked out. A fully explicit finite difference scheme, an implicit finite difference scheme and different combination of the two, with varying values of weighing factor were thoroughly studied. All the possible options of temperature-time grid sizes were considered. It was found that the simplest explicit finite difference scheme with ten characteristic length division and Fourier number increments one sixth of the square of the space division size gives best convergence and minimal truncation error. Numerically computed and measured temperature-time variations were found to have excellent agreement.