You say you are in Queens...which LFS sold you those mandarins? While I would expect Fishtown would sell them without hesitation, I know H2O and Aquatic Visons wouldn't sell them without at least warning you. This hobby has nothing written in stone. So, yes, I believe that sometimes mandarins can be kept in a 10 gal tank. Sometimes they will eat frozen food- I even witnessed a mandarin chomp down on Formula 2. But these are the exceptions. For the average aquarist, under average mandarin conditions, they will need large, old, mature reef setups. While 55 gal is the usual stated minimum, there is wiggle room there. Even under the best conditions, if the mandarin spent more than 5 days in the LFS, it is most likely too far gone to survive in a tank. I wouldn't recommend buying a mandarin that has spent more than 2 days in an LFS. I haven't even had luck with them recently...while they used to last many years, my last few haven't made it- and my 55 gal is crawling with pods, amphipods, and tiny sandworms. Take care, Eric