|Armed with grenades and ready to blow your face off.|
Peach Wilkins is a resident of Neptune's Bounty, and appears to be the leader of Fontaine's crew of illicit smugglers. He is a paranoid man with a stereotypical "wharf rat" manner of speech. The story of Peach Wilkins began long before Rapture fell into its current state. Back in the day, Fontaine had promised Wilkins something "better", and told him that he wanted to meet with him after hours at the fisheries. After this meeting, Peach Wilkins and a group of men became smugglers for Fontaine's surface goods.
After Andrew Ryan began cracking down on Fontaine's smuggling ring, most of the smugglers were either caught, or found dead before they could be interrogated. It is unclear whether Peach himself had turned Fontaine into Ryan's men, or if he was just eventually caught in the act. After Fontaine's assumptive "death" Old Peachy became more and more paranoid that Fontaine was still alive and out to do him in. As a result, Peach Wilkins and the remaining smugglers decided to seal themselves inside the freezer of Fontaine Fisheries - in hopes that they would be protected from Fontaine's wrath.
Peach Wilkins plays a relatively large role in the Neptune's Bounty part of the game as the leader of the remaining smugglers. Jack's first "encounter" with Wilkins starts at the entrance to the freezer, where he initially fights a Spider Splicer for the first time, and fails to kill it. Right from the start, Peach Wilkins makes a few remarks which already places him as a paranoid delusional madman. This is later reinforced when he insists that all weapons must be placed in the pneumomatic before he allows anyone to enter the freezer. In Jack and Peach Wilkins' initial conversation Wilkins also makes a remark that Atlas had radioed ahead to let him know about Jack, and if Atlas had vouched for Jack, then he might be trustworthy, but later he recants this position when he claims that Atlas is no better than others for bringing him an agent of Andrew Ryan.
During the initial conversation Peach Wilkins advises Jack that if he wants to enter the freezer he must provide 3 research photos of the Spider Splicers, which will also allow him to find their weakness and kill them more easily.
 About the Fight
Peach Wilkins is both treacherous and paranoid, and has laid a trap for you, but luckily you can prepare for this fight! Right after you enter the outer door of the freezer you will be able to pick up some hypos (you may have to melt some of the ice on the floor). There is a Gene Bank here, and you should consider equipping the Telekinesis plasmid if you do not already have it equipped (Peach Wilkins is essentially like a Nitro Splicer and throws incendiary "grenades" at you).
Before the battle begins be aware that the room is split into two parts - the front and the rear portion. You start off at the rear portion, and this is where you want to stay because at the far end there is a turret and a security camera, which will greatly reduce your chances of survival. In the half of the room where you should stay there is a healing station so if you are in big trouble you can make use of that.
For this fight you will have no projectile weapons on you, but this is not a problem. With Telekinesis, Incinerate and the wrench you can take out all the enemies that come at you. At the beginning of the fight there is a lot of smoky mist like you would find in a large freezer, so visibility is a problem - but start by equipping your Telekinesis plasmid and wait for Peach Wilkins to reveal himself. He starts by throwing his explosives at you, and a good strategy is to grab those grenades with Telekinesis and throw them at the other Splicers who are shooting at you with their weapons. These other splicers come in groups of 2 and are not a huge threat to you if you manage to catch all of Peach Wilkin's grenades. After you take out the first wave of mobs, you should probably kill Peach Wilkins (with his own grenades, oh sweet irony!) and then take out any remaining Splicers using your wrench.
After the fight you should hack the turret and the security camera. You will notice that you can probably melt the blobs of ice blocking each of the large freezer "containers" in the room, but do not open these until you retrieve your weapons (stored at the pneumo at the middle of the stairwell below the turret).