Cyanobacterium producing cylindrospermopsin cause oxidative stress at environmentally relevant concentrations in sub-chronically exposed tilapia (Oreochromis niloticus)

► Cyanobacterial cells containing CYN and deoxy-CYN induce oxidative stress in fish. ► Kidney of tilapia exposed to cells was more affected than the liver. ► The lowest concentration assayed (10 μg L−1) caused damages after 7 d of exposure. ► Toxicity of CYN- and deoxy-CYN-containing cells was time and dose-dependent. ► Exceeding 10 μg CYN or deoxy-CYN L−1 would be considered of high risk for fish.