Abstract We report on the analysis of fish bones of the African catfish, Synodontis schall (schall), recovered from the site of Tell el-Amarna in Middle Egypt. A systematic programme of sampling and sieving at this site has resulted in a large and well-preserved faunal collection from Pharaonic (14th century bc ) and Late Roman (5th–6th centuries ad ) deposits. Bones of schall are well represented, and in particular the pectoral spine, a robust and well-preserved anatomical element, which contains a record of incremental growth structures. We present here our methods of analysis, using a sample of modern schall collected at monthly intervals over a 12-month period to validate the interpretation of the incremental growth structures. We use these methods to identify variations in size and growth characteristics between Pharaonic, Roman and modern material and to throw light on changes in the ancient Egyptian economy and the ecology of the Nile. Our results demonstrate that the schall of the Late Roman period grew more slowly and were subject to more intensive levels of fishing pressure than those of the Pharaonic and modern periods. We interpret this as evidence of climatic deterioration and a concomitant increased reliance on fish for food during the 5th–6th centuries ad .