As stated above, no SW shark can live in a 220gallon for live. They only type of shark that could work possible would either be a Marbled Cat Shark or Coral Cat shark. However I see 250gallons as being the minimum. Now as for the shark you are describing, only shark which comes to mind that could have possible lived in that tank without dieing that resembled a Great White could have been either a Brown or Gray Smoothhound. However they need atleast 1,200 gallon to live somewhat a happy life. So what your friend was doing was horrible, and absolutly un-ethical. No SW shark available in the aquaria trade could thrive in a 150 gallon for more than a year possible two max! So I think you should do a little research, and get some SW experience under your belt before trying to pursue keeping a shark.