Fish model is a development model.It is a time consuming and expensive model, One can be rest assured that both verification and validation is done paralley by separate teams in each phase of the model. So there are two reports generated by the end of each phase , one for validation and one for verification. The structure of this model looks like a skeleton between two parallel lines, hence the name fish model.This process results in products of exceptional quality but it is time consuming and expensive.
V model assures highest quality of the product.Apart from checking and process checking, there is a separate test management process to re-ensure the quality of testing. This test management helps in calculating the efficiency of a software.The software got results is of the Highest quality possible.It is also time consuming and expensive.