Hey there! In order to solve this problem, you'll need to determine the probabilities of picking a blue fish from both of the tanks, then multiply these together to get your final possibility. You can just multiply these together since they are independent events and don't affect each other.  $\frac{9}{17} * \frac{6}{12} = \frac{9}{17} * \frac{1}{2} = \frac{9}{34}$ There will be a 9 in 34, or about a 26% chance, of choosing two blue fish. Hope this helped you out! :-)