During April 2025, Fillfish focused on enhancing code maintainability and clarity across four repositories, including nspcc-dev/neofs-node and redpanda-data/console. He improved backend code by standardizing naming conventions and refining test identifiers, which streamlined code reviews and reduced onboarding friction. In filecoin-project/lotus and celestiaorg/celestia-app, he addressed documentation bugs by correcting function comments and fixing typographical errors, ensuring that documentation accurately reflected code behavior. Working primarily with Go, Fillfish applied backend development and code refactoring skills to deliver updates that preserved existing functionality while improving long-term readability and maintainability, demonstrating a methodical approach to incremental codebase improvement.