The inaccessibility of credit by farmers has been identified as a limitation to sustainable agriculture. This study examined the effectiveness of Agricultural credit on the productivity of cat fish farmers in Anambra State, Nigeria. Data collected from 150 respondents were analyzed with descriptive statistics, t-test and multiple regression. We confirm that only 46% of the farmers had access to credit, while, personal saving was the main source of capital for the cat fish farmers. Their average stock size, and output were 590, and 570 fishes respectively. A statistically significant difference existed between the stock size, output, casualties, and number of ponds of farmers that had access to formal credit and the farmers that had no access. Drivers of farmers’ output were marital status, sex, educational level, experience, and credit. Farmers’ access to credit was constrained by many factors. We recommend that Government and financial institutions should partner with legal aid organizations or government agencies to streamline the process of acquiring documentation to assist fish farmers in obtaining the necessary legal documents required for securing loans. Also, the fish farmers should form/strengthen cooperative groups among themselves to facilitate access to finance.