#3 Prejeck Paddle Fish
Sadly, all that time you spent collecting every last fish for your aquarium in Mass Effect 2 was a waste, as they don't carry over into Mass Effect 3. The good news is, really dedicated players can keep the priciest specimen in their collection, the Prejack paddle fish.
To get it back, you'll need to import a save file that meets a fairly stringent list of prerequistes from the last game. First, you'll obviously need to purchase the fish from the shop called Memories of Ilium. Next, you'll need to have kept it alive until the end of the game. Third, you'll need to seduce Kelly Chambers enough that she'll agree to look after your fish. Finally, you'll need to make sure she survives the ending sequence at the Collector base.
If your imported save meets all those criteria, you'll be able to meet up with Kelly at the Citadel refugee camp. Talk to her, and she'll return your prized paddle fish.
