You can use the minimap to zoom in but it is still difficult to tell if the color is similar. It makes sense anyway to have a filter so you can tell your enemy from allies or neutral. I was playing gigantic and one of the races had so many ships flying around that I had trouble spotting the one I was at war with. I could see almost the entire galaxy but they kept going near the other ai. There would be 6 fleets from 1 guy and then the 1 from the enemy. Sometimes I would not notice until they attacked a transport that I thought was safe or landed on a planet.