firstly, rhomboid is a deep water fairy wrasse that is prone to decompression issues and shipping stress. especially the large males.
the larger they are, the worst they ship.
almost 80% of rhomboids will die from decompression problems when shipped. it's not the LFS fault. it's the handling and collection fault. people in japan, U.S and thailand also have problems with large male rhomboid wrasse. so the solution, either you're lucky, or buy smaller males/females or juveniles.
secondly. cyanide is not used anywhere else except indonesia and philippines. so please get this right.
3rdly, angels like flame angel, lemonpeel etc are very prone to flukes. as said before, it's not the LFS fault. these fishes come in with problems like this from the wild. i always do a 10 min freshwater dip to all angels and butterflies i buy to de-fluke them.
all the problems above are NOT the LFS fault.
of course, LFS in singapore are not good at holding fishes for too long. but i assume you bought the fish on the same day of shipment. so this is still fresh and in good condition.
if you bought it like many weeks after shipment, then there could be a problem since most LFS here are not good at holding fish too long.
so before fingers are pointed at any LFS, please look deeper into the problem and not superficially.