They will take warmer water for a while at least, and one thing to remember is they are not long lived fish even in the wild. Public aquariums can not keep them alive for more then 2 years and 1 is the average, it seems that even in the wild they are seasonal fish and 1 to 2 years is about all they live. I have spoken to aquarists in both Steinhart and Monteray Bay Aquariums about them and that is just their lifespan. When you see them in a store they are already adults and who is to say the age of an individual, if it is 9 months old when you buy it then maybe 3 more is not a premature death. Still, I do not agree with catching them for the pet trade and a chiller with the water kept in the very low 70's as the highest temps reached would be what you would need to keep them.