Contents: 1. INTRODUCTION TO TOXICOLOGY 2. HISTORY OF TOXICOLOGY 3. POISONS, THEIR CLASSIFICATION, UNTOWARD EFFECTS, DIAGNOSIS AND TREATMENT 4. HEAVY METAL TOXICITY IN FISHES 5. NON-METAL TOXICITY IN AQUATIC SPECIES 6. PHYTOTOXINS IN AQUACULTURE 7. TOXICITY CAUSED BY AGROCHEMICALS 8. MICROBIAL TOXINS 9. TOXICITY OF DRUGS AND CHEMICALS USED IN AQUACULTURE 10. MAXIMUM RESIDUE LEVEL (MRL) OF DRUGS AND CHEMICALS IN FISH 11. DETOXIFICATION MECHANISMS OF TOXIC SUBSTANCES BY AQUATIC ORGANISMS 12. ANTI-NUTRITIONAL FACTORS AND THE METHODS OF DETOXIFICATION 13. Genotoxicity