So I was talking to others, and everyone seemed to agree... for Robot fish, the water areas are slim pickings. There's 1 spot, 2 servers. 2 places to fish for them total. Only place I can think this is the same would be Petropolis, but that's a much larger body of water (so more fish spawn).
I was thinking we should fill the hole to the left of Robo City with water (see attachment for the hole I'm talking about). It would add another spot for fishing robo fish (big and little), and I know everyone would appreciate it.