hey, Im new to this site as well as to aquariums. I set up my first 75g fresh water aquarium cycled it and put my first fish (Red Tail Dorado Cuda about 6in). Now I want to add more fish. I was thinking maybe on more cuda and 1 payara. what other nice aggressive fish would mix and how many can i stock. also is it a good idea to add carb and a crayfish electric blue? Which payara would be appropriate for my tank?