These bacteria produce a red color when grown at temperatures below 35-37C, but do not produce this pigment at higher temperatures, resulting in a pale off-white color. Also, the bacteria produce more red color when they're grown at higher densities [more crowded], and they produce less pigment in nutrient-poor media, whether the bacteria are crowded or not.

So hot or starved bacteria would be pale, and red-colored bacteria would be found at cooler temperatures [35-37 degrees centigrade] and when they're well fed. The part about crowding is confusing, because they're red if they're crowded and well-fed, but they're pale if they don't have enough food, even if they're crowded.

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