Highlights•We evaluated β-glucan for alleviating ammonia stress inTor putitora.•A decrease in transcript level ofinoswas observed in β-glucan-fed ammonia-challenged fish.•β-Glucan had no effect on most of the immune genes of ammonia-exposed fish.•Aquaporins 1a and 3a expression decreased in β-glucan-fed ammonia-exposed fish.•Feeding 0.75% β-glucan improved resistance to ammonia stress inT. putitora.