The ever increasing demand and depletion of fossil fuels along with environmental concern has prompted search for alternate fuels. The selection of optimum biodiesel with the appropriate blend for the IC engine plays a vital role in the energy sector. This paper describes the application of novel hybrid multi-criteria decision making (MCDM) technique to evaluate the optimum fish oil biodiesel blend. Fuzzy TOPSIS and fuzzy VIKOR are used to evaluate the best blend, where fuzzy is to determine the relative weights of the criteria, TOPSIS and VIKOR has been used for obtaining the final ranking of alternatives. A four stroke single cylinder, constant speed, direct injection with a rated output of 4.4 kW was used for exploratory analysis. The ranking performance of both the methods is also compared with each other and selected B40 is the best blend to operate the engine. The proposed MCDM models are simple, precise and efficient tool for the decision makers to identify the suitable blend among the alternatives. Copyright © 2020 Inderscience Enterprises Ltd.