The oceans cover most of our planet and are home to an incredible variety of life. Scientists have worked hard to describe and understand the many species of marine life, especially large animals that are easier to see and study. However, small or hidden creatures, known as "cryptofauna", often get overlooked. Among these are parasites, which are one of the most common and important types of organisms on Earth, yet they are often left out of research because they are small and difficult to find. Our research will study parasites in coral reefs, which are some of the most diverse and threatened ecosystems in the world. Specifically, we are studying a group of tiny parasites called apicomplexans, which live in the blood of coral reef fishes. These parasites are related to others that infect land animals, like malaria. The goals of our project are to: 1) find out how many species of these parasites live in reef fish and where they are found; 2) use DNA tools to help identify and organize them; and 3) teach students how to study these small but important animals. Parasitic organisms are a key part of cryptofauna biodiversity. Parasitism is the most common animal lifestyle, and most common biological interaction, evolving multiple times and in nearly every animal taxon. Because of their effects on host population dynamics, parasites have additional direct and indirect influence on the biodiversity of ecological communities in general. The goal this project is to understand the