The small team of autonomous robotic fish (STARFISH) project was conceptualized to explore the use of multiple cooperative autonomous underwater vehicles (AUVs) for underwater sensing and monitoring applications. To support this exploration, the STARFISH AUVs were developed as low-cost, open-architecture AUVs with a high degree of modularity and reconfigurability. This makes them an excellent research platform for testing of novel algorithms and research payloads. The vehicles not only featured a high degree of electrical, mechanical and software modularity, but also explored use of an agent-based command & control system modeled on a typical naval command hierarchy, low-cost obstacle avoidance scanning sonars, online system identification, vectored thrust using miniature Voith-Schneider propellers, cooperative acoustic & terrain-aided navigation for improved accuracy, and numerous sensor payloads. STARFISH AUVs are designed to work cooperatively with other AUVs or autonomous surface vehicles (ASVs), achieving complex tasks at low cost.