Most aquariums tend to keep a mix of green, hawksbill, and loggerhead sea turtles, with olive ridley being somewhat rarer but still around. I've read that leatherbacks cannot be kept alive in captivity, but are there places with occasional rescue animals? As for the remaining two species, which institutions keep Kemp's ridley and flatback sea turtles? Are there any Kemps kept outside of the US, and any flatbacks kept outside Australia? And how common are these two in the aquariums of their respective countries?