The arthopod class Crustacea has a widely known and vast fossil record. Despite this, the fossil record for Astacoidea and Parastacoidea, both groups including crayfish, is minimal compared to the related lobsters. A fifteen-week project was conducted to study the decomposition patterns of both crayfish and Penaeus (shrimp) in various simulated clay, aquatic environments. This experiment was conducted to make inferences on why the crayfish fossil record is sparse while also studying how early stages of decomposition could affect fossilization. The experiment was conducted under the assumption that crayfish exoskeletons appear to be much stronger and denser than shrimp; therefore, crayfish would take significantly longer to decompose and would leave a large remainder of its harder exoskeleton undecomposed. However, it was proven that shrimp decompose at a much slower rate, which helps explain the differences in the two species fossil record. Freshwater versus marine water environments did not experimentally demonstrate differences in decomposition rate.