The one-day training workshop entitled "Identification of sexual maturity stages in fish using histology" was held in the presence of university students and researchers from various research centers in the theoretical and practical sessions in the meeting room and aquatic physiology laboratory of the department of production, reproduction and selective breeding of aquatic organisms of the National Inland Water Aquaculture Institute, dated 4 February 2019. Dr. Mohadseh Ahmad Nejad, the physiology lecturer, explained the importance and records of histology, the use of histology in the fisheries sciences, the process of fish reproduction, the various stages of sexual maturity, the way to determine the time of sexual maturity, the various stages of classical histology, the way to conduct experiments and applied projects on physiology and histology studies. Then, in the practical part of the workshop, the learners under the supervision of Mr. Dezhandian were acquainted with the stages of histology operations and microscopic examination of histological sections of the fish gonads.