Meet Our Qualified Providers
The providers at Bywater Mental Health are a dedicated and compassionate team of mental health professionals committed to helping individuals on their journey to emotional well-being. With a diverse range of expertise and backgrounds, they offer a wealth of knowledge and experience to address a wide spectrum of mental health concerns.
Dr. Zachary Zimko is a Licensed Osteopathic Physician in the state of Florida. He graduated Cum Laude from the University of Delaware in 2012 with a B.S. in Neuroscience and Minors in Medical Humanities, Medical Diagnostics, and Biology. He graduated from Rowan School of Osteopathic Medicine in 2016 with a Doctorate in Osteopathic Medicine. He graduated his Psychiatry Residency at Largo Medical Center in 2020 and was Chief Resident in his final year. He is Board Certified in Psychiatry through the AOA. He served as Medical Director of PEMHS for 3 years. He is currently an Assistant Professor at USF Health, Morsani College of Medicine’s GME program at Largo Medical Center and a member of the Pinellas EMS Advisory Council. He co-founded Bywater mental health in 2021 with Dr. Randall to provide quality psychiatry services in Pinellas County. His hobbies include cooking, home-brewing and spending time with his Wife, Daughter, and Corgis (Luna & Lilly).
Dr. Gerald Randall is originally from a small town in Western NY near his favorite place to visit, Letchworth State Park. He is a graduate of Syracuse University with a Bachelors of Science in Biology. He obtained his Osteopathic Medical Degree from Lincoln Memorial University-DeBusk College of Osteopathic Medicine in Harrogate Tennessee. His residency was at HCA Florida Largo Hospital, Formally Largo Medical Center, completing his training as Chief Resident in 2018. Dr Gerald Randall is a board-Certified Psychiatrist, Co-founder, and Co-owner of Bywater Mental Health. In addition to his outpatient Psychiatric practice, he is an attending Psychiatrist at HCA Florida Largo West Hospital, Faculty Psychiatrist and Chairman of the Clinical Competency Committee at HCA Florida Largo Hospital Psychiatry Residency. He also serves as a Staff Psychiatrist at PEMHS and at HCA Florida West Tampa Hospital. Dr, Randall specializes in the care of adults with mental illness. He has special interests in the treatment of individuals with Autism, PTSD, Veterans/First Responder/EMS and individuals with ADHD. He is inspired daily by his three children, two of which are diagnosed with Autism and his wife who dedicates herself to the care of their Neurodivergent children. In his spare time, he enjoys fishing with his family, attempting to walk the family Bernese Mountain dog named Hans and exercise.
Dr. Christina Mathew MD is an allopathic physician licensed in the state of Florida. Dr. Mathew earned her undergraduate B.A. degree in Chemistry, graduating Cum Laude from Hope College and her Doctor of Medicine degree from Michigan State University College of Human Medicine. She completed her psychiatry residency at HCA Healthcare/USF Morsani College of Medicine at Largo Medical Center, where she received broad training across multiple psychiatric specialties. She is board-certified in psychiatry through the AMA. Dr. Mathew is committed to providing quality psychiatric care to help patients achieve lasting mental wellness. Her interests include spending time with her husband and daughter, cooking, reading books and traveling to the best food destinations.
Danielle Thompson, APRN is a psychiatric mental health nurse practitioner board-certified through the American Nurses Credentialing Center (ANCC). She completed her degree as a Registered Nurse at Helene Fuld College of Nursing in New York City. After 18 years of nursing experience specializing in neurology and psychiatry, Danielle trained directly with Dr. Zachary Zimko while she completed her Master of Science in Nursing from Herzing University. Danielle is an active member of several professional organizations, including nursing’s international honor society, Sigma Theta Tau, the American Psychiatric Nurses Association, and the Neuroscience Education Institute. Danielle lives in Tampa with her husband of 10 years and two children. She is an avid foodie who loves to travel, attend concerts, and appear as background talent in movies. In collaboration with Dr. Zachary Zimko, D.O., and Dr. Gerald Randall, D.O., Danielle’s role is to assess, diagnose, and treat mental illness in outpatient and inpatient.
Isaiah Millstein is a Registered Marriage and Family Therapist Intern in the state of Florida. He earned his Bachelor of Science in Health Services Administration from St. Petersburg College and his Master of Science in Marriage and Family Therapy from Capella University.
Isaiah works with individuals, couples, and families navigating anxiety, burnout, relationship stress, identity development, LGBTQ+ concerns, family-of-origin patterns, and major life transitions. He especially enjoys supporting thoughtful, motivated clients who may appear high functioning on the outside but feel overwhelmed, stuck, or disconnected internally.
Using Solution-Focused Brief Therapy and Cognitive Behavioral Therapy, Isaiah helps clients recognize their strengths, clarify their goals, strengthen communication, establish healthy boundaries, and move beyond repetitive cycles of overthinking or conflict. His therapeutic style is warm, direct, collaborative, and affirming, with humor incorporated when appropriate. He strives to create a judgment-free environment where clients feel safe being their authentic selves while developing practical tools for meaningful and lasting change.
Outside of therapy, Isaiah enjoys traveling, exploring new places, attending concerts, and spending time with friends and family.