System and methods for collecting and preparing fat for autologous fat transplantation. The system includes a centrifuge, syringes, and filtering and transferring assemblies coupled with the syringes. Substances, including oil, fat, and denser substances (tumescent fluid, connective tissue, and other non-fat substances), are harvested into a syringe. A dye is provided or injected in the syringe. Centrifugation of the syringe stratifies the substances into a top oil stratum, a middle fat stratum, and a bottom denser substance stratum. A superficial layer of less viable fat tissue in the middle stratum is highlighted by the dye. Denser substances are filtered out of the syringes during centrifugation. Oil and the less viable fat tissue are removed through a port in the plunger head of the syringe plunger. More viable fat tissue is transferred into smaller syringes through an adapter in the assembly coupled with the syringe and the smaller syringes.