This dataset contains ecotoxicity results from experiments conducted as part of the EU TransPharm project. It covers six compounds tested on four aquatic species: the cyanobacteria Microcystis aeruginosa and Anabaena flos-aquae, the green alga Raphidocelis subcapitata, and the crustacean Daphnia magna. The compounds comprise two marketed fluoroquinolones (ciprofloxacin and ofloxacin), three analogues (ciprofloxacin-hemi, ofloxacin-hemi, and amine-ofloxacin-hemi), and a degradation product of ciprofloxacin-hemi. Tests were conducted in accordance with relevant OECD guidelines.