The release of textile effluent into the natural waters poses a serious threat to the aquatic ecosystem. Here, SnO2/GO nanocomposites were synthesized with tunable morphology by the addition of GO with a sonochemical method. The material was characterized using X-ray Diffraction (XRD), scanning electronic microscopy (SEM), Ultraviolet-visible spectroscopy (UV–vis), and infrared spectrometry (IR). The photocatalytic degradation of Rhodamine B (RhB) and textile dye wastewater (TDW) using SnO2/GO nanocomposites was studied under sunlight irradiation. The SnO2/GO nanocomposites exhibited high photocatalytic activity towards the degradation of RhB and TDW with up to 95% removal efficiency. The catalyst dosage, concentration variation, and reusability of the catalyst were also examined to optimize the reaction conditions for the degradation of dye. Bioassays were used to investigate the survival growth rate of simple food webs such as Chlorella pyrenoidosa (CP), Artemia salina (AS) and Danio rerio (DR) in the treated and untreated solution. These simple food web model animals showed good reliability for analyzing the toxicity of the treated and untreated wastewater. Further, histology was analyzed to find out the influence of the dye solution in the animal model. These results suggest that the SnO2/GO nanocomposite shows promising efficiency in the wastewater treatment, which is further confirmed in the toxicity analysis. © 2020 Elsevier B.V., All rights reserved.