Tilapia are some of several commercially important aquaculture species (including trout, barramundi, and channel catfish) susceptible to off-flavors. These 'muddy' or 'musty' flavors are normally caused by geosmin and 2-methylisoborneol, organic products of ubiquitous cyanobacteria that are often present or bloom sporadically in water bodies and soil. These flavors are no indication of freshness or safety of the fish, but they make the product unattractive to consumers. Simple quality-control procedures are known to be effective in ensuring the quality of fish entering the market.