Contents: 1. Introduction 2. Mendel’s laws of inheritance 3. Inheritance of qualitative traits in fish 4. Cells and chromosomes 5. Genes 6. Gene interactions 7. Genetics of quantitative inheritance 8. Sex determination 9. Sex linked genes 10. Hybridization in fishes 11. Mitochondrial inheritance 12. Mutation 13. Linkage and crossing over 14. Chromosome manipulation 15. Cryopreservation 16. Population genetics 17. Inbreeding and crossbreeding 18. Domestication in fishes 19. Sex-Reversal in fishes 20. Selection methods in fishes 21. Genetic improvement of fish and shell fish for disease resistance 22. DNA markers in fisheries application 23. Aquatic genetic resources and its conservation 24. Fish seed certification and quarantine