Fish-pathogenic flavobacteria (Family Flavobacteriaceae) cause substantial losses in US hatcheries and aquaculture facilities. These infections are especially problematic for trout during early life stages and are transmitted along with the eggs and reproductive fluids of infected spawning fish. In attempts to prevent flavobacterial transmission, fish producers and hatchery managers utilize several disinfectants, one being iodine, which is commonly used for egg surface disinfection. Unfortunately, such treatments often produce inconsistent results, a matter likely exacerbated by the diversity of flavobacterial species which are increasingly being recognized as emerging fish pathogens. With the ultimate goal of devising more efficacious flavobacterial prevention and control methods, this study evaluated the in vitro susceptibility of a range of flavobacteria to several topical disinfectants. In an ongoing study, >500 flavobacterial isolates (Flavobacterium spp. and Chryseobacterium spp.) were recovered from rainbow trout (Oncorhynchus mykiss) eggs, fry, broodstock and rearing water in facilities in Michigan, Minnesota, Ohio, Pennsylvania, and Idaho. >60 Flavobacterium and Chryseobacterium isolates belonging to >30 distinct phylogenetic clades were tested for their in vitro susceptibility to chloramine-T (10-40 mg/L), formalin (150-2000 ppm), hydrogen peroxide (100-1000 ppm), and iodine (50-800 ppm) at durations of 1, 10, and 30 minutes. The degree to which some of these commonly utilized compounds killed flavobacteria varied. For instance, 1000 ppm formalin (30 min) was effective at killing all tested Flavobacterium strains, but not all Chryseobacterium strains. Likewise, hydrogen peroxide at 100 ppm (30 min) varied widely in flavobacterial killing efficacy (i.e., 13-100% growth reduction), yet 100% reduction was achieved at 500 ppm (30 min) for all tested strains. In contrast, all assayed flavobacteria were killed by chloramine-T at the lowest tested concentration (10 mg/L; 10 min) and were likewise all rapidly killed by iodine exposure (50 ppm; 1 min). Paradoxically, this included isolates that were originally recovered from trout eggs that had been disinfected with 400 ppm iodine prior to sampling. Collectively, findings highlight the complexities involved in halting flavobacterial transmission from parents to offspring, but also provide insight for developing more efficacious methods for preventing and controlling flavobacterial disease outbreaks.