Fish may be exposed to Chromium (Cr) waste which is released into aquatic environments through electroplating tannery and textile industries. Therefore we examined the effect of hexavalent chromium on the reproductive and patho-physiological changes of blue tilapia (Oreochromius aureus) with trials to improve these hazard effects by addition other adsorbant substance. A total number of 270 O. aureus (40-45 g/fish) were divided into 9 equal groups (each subdivided into 3 equal replicates). The 1st group was used as control, meanwhile 2nd and 3rd groups received 1/8 and 1/4 LC50 of Cr (4.925 and 9.85 mg Cr /l), respectively. Other groups received the same doses of Cr, in addition to 0.3 g/ l of EDTA (group 4 & 5), super phosphate (group 7 & 8) and charcoal (group 8 & 9). Sampling was done from each at 7, 30 and 75 days after experiment start. Fish exposed to Cr showed significantly reduced growth; which was improved when EDTA, super phosphate and/ or charcoal were added with Cr. A significant reductions (P
Key words: tilapia, chromium, chelating agents, haematology, biochemistry and histopathology
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