:barfPick it up and smell it. If it's dead you'll have a very strong urge to vomit. They get a smell like week-dead rat instantly as soon as they die it seems. If it's just a faint fishy smell, its still alive.
thank you! i bought two of them one is fairly active (get something against my decoration) but the other is really peaceful. already checked them they smell ok and he/she kept his door shut. thanks