Hematologic and hepatic responses of the freshwater fish Hoplias malabaricus after saxitoxin exposure

► Fish exposed to saxitoxin (STX) on Hoplias malabaricus through trophic bioassay. ► Mean corpuscular hemoglobin concentration and mean corpuscular hemoglobin increased in the STX group. ► The hepatic tissue from both groups exhibited a typical pattern that have been already described for most teleost fish. ► The results suggested the generation of reactive oxygen species. ► STX caused liver biochemical alterations that can be considered ecologically relevant.