The aim of this study was to determine the median lethal concentration (LC_50−96h), effective concentration (EC_50−96h), risk assessment, and development of Nile tilapia Oreochromis niloticus larvae submitted to florfenicol (FF) exposure. Fish (n = 147; 8.6 ± 0.6 mg; 7 fish/aquarium) were randomly distributed in 21 aquaria (1 L) and exposed to five concentrations of FF 58.73; 131.31; 198.96; 241.88 and 381.81 mg L⁻¹ plus one control and a control with solvent, totalizing seven treatments and three replicates. The estimated median LC_50−96h of FF for Nile tilapia larvae was 349.94 mg L⁻¹. The EC_50−96h of FF was 500 mg L⁻¹ for weight reduction and was 1040 mg L⁻¹ for length reduction. After the exposure period, final weight and length differed (p < 0.05) among treatments, showing the lowest biometric values ​​with the highest concentrations of FF. The pH and dissolved oxygen were altered (p < 0.05) during the experimental period. The FF high doses used to determine the LC 50 after 96 h negatively affected the development of the larvae. On the other hand, through risk assessment analysis this antibiotic can be classified as low toxicity to Nile tilapia larvae and show low environmental risk.

这项研究的目的是确定接受氟苯尼_考（FF）暴露的尼罗罗非鱼尼罗罗非鱼幼虫的中值致死浓度（LC _50-96h），有效浓度（EC _50-96h），风险评估和发育。鱼（n = 147； 8.6±0.6 mg； 7条鱼/水族馆）随机分布在21个水族馆（1 L）中，并暴露于五种浓度的FF 58.73；131.31; 198.96; 241.88和381.81 mg L ^-1加一个对照和一个带溶剂的对照，总共进行7次处理，重复3次。尼罗罗非鱼幼虫的FF的估计中值LC _50-96h为349.94 mg L ^-1。FF的EC _50-96h为500 mg L ^-1为了减轻重量，为1040mg L ^-1以减少长度。暴露期后， 治疗之间的最终体重和长度不同（p <0.05），显示出最低的生物测定值和最高的FF浓度。 在实验期间，pH和溶解氧发生了变化（p <0.05）。96小时后用于确定LC 50的FF高剂量对幼虫的发育产生负面影响。另一方面，通过风险评估分析，该抗生素可被归类为对尼罗罗非鱼幼虫低毒性，并显示出低环境风险。