As far as my limited human perspective is concerned, I’d rather be kept safe, have someone fussing over me, keeping me well-fed and fat, and experience a bit less freedom in some ways than have all the choices and all the room in the world to make them but whatever I end up with is a crapshoot and I may well lose my life earlier than I should. And this, my friends, is why I’ll get married hopefully soon.
However, this doesn’t mean we should buy any animal without the ability to give it what it needs to thrive in our captive environments. This means making the tank fit the fish, rather than forcing the fish to fit the tank. This means taking factors like tank mates, stocking levels, amount of maintenance we are willing and able to do, rock work, water temperature and other things into ample consideration.
There are a number of species of fish that are often sold as tropical fish, but really need cooler water temperatures than the average reef tank (76-80). One good example would be the Blue Spot Jawfish. And I can think of many other deepwater fish that really ought to be kept at lower temperatures and I can’t help but think they’d do better at lower temperatures. For example, Genicanthus Semifasciatus and Genicanthus Watanabei may well be able to adapt to typical reef aquarium temperatures, but in the wild they usually live below 150 feet. This means a temperature in the low seventies may well suit them better unless they’re captive bred at some point.
Blue Line Angels, depending on their point of collection (the Vietnamese ones may not really matter in this case), might also do better at lower temperatures (low seventies) if they were collected from places like Japan or northern Taiwan. Northern Taiwan is still a bit too cold for full-blown coral reefs and it’s only when you get to the southern part of the island (as in Green Island, Orchid Island, and Kenting) near the Philippines do we see fully tropical reef systems.
Other examples I can think of are C. Interruptus (maybe the ones from the NW Hawaiian Islands don’t present these problems?) from Japan, H. Clarionensis, P. Zonipectus, and maybe H. Passer, specimens collected from the northern parts of their distribution (as in Baja) where the water’s not warm enough for full coral reefs may do better with cooler temperatures than specimens collected from further south in Mexico and the Central American coastline.
Wild caught Bandit Angels from the main islands are caught in deeper waters, usually 150 feet and below. IMO unless captive bred A. Arcuatus might also thrive under cooler temperatures. The elusive G. Personatus if wild caught, is often caught in very deep water in the main islands.
About 10 years ago copps mentioned how his pair of G. Semifasciatus weren’t liking the 76-80F of his main reef tank, some he moved them to his FOWLR in the low seventies and they liked it more. He ended up replacing them with a pair of G. Lamarck which are found in shallow water.
