Coloration doesn't "mean" anything, lol. It's just what the seahorse chooses to be. We can try to encourage different colors by providing specific colored hitches, but it doesn't always work. Mine seem to always turn yellow / orange or stay black. I don't care what color they are as long as they are healthy. I do like the yellows and oranges though. It adds a nice splash of color to the tank. Sometimes color can indicate illness or water quality issues. I've never depended on this since they can be 100% healthy and still be dark or light in color.