hi mate , just about all stores keep all channa at tropical temps , a lot of shops are on full systems so hard not too , others just do not know any better.
i would advise against keeping it in full tropical temps all year round , the best you could acheive is to set the tank to 25deg and most tropicals would be fine with that also. but really they are best kept in a species tank , and in a community esp. tropical you would most likley find that it would just hide away most of the time , and could go off its food.
you can actually tell in the pic that the fish is not at optimum conditions as it is stressed and all colours and markings are poor.
i think you have done great researching what you are going to buy and you should go with the info you have found , it will save you time and money in the long run
cheers col