Fish are a key source of food and nutritional security for poor riparian households. These factors are particularly important during periods of stress, such as during the COVID-19 pandemic, which made communities vulnerable to food supplies. Therefore, understanding fish dynamics in flood-pulsed floodplains is essential for the sustainable utilization of fisheries resources. Fish samples were collected from a seasonal floodplain habitat using standard techniques over a 5-month flood period. PASGEAR was used to manage and analyse some of the data, while the coefficient of variation (CV) was used to estimate fish community stability along a seasonal hydrograph. A total of 7369 fish specimens were collected during the study period; 47 of these species belonged to 11 families. The results showed that the populations of the top five most species (based on the percentage of the index of relative importance, %IRI) fluctuated (CV ≥ 76%) over the study period. Moreover, CV analysis revealed that the overall fish community also fluctuated over the study period (CV = 198). Generally, this suggests that fish species are highly mobile in floodplains and are possibly utilizing newly opened habitats within a limited window of opportunity. Possibly, the arrival of new floods opens up new foraging opportunities and ecological habitats for different fish species in the seasonal floodplains. Therefore, this study provides contributes to the body of knowledge on the dynamics of fish communities within seasonally flooded floodplains, which is key towards floodplain fisheries management. In conclusion, floodplain fish communities are highly mobile, which makes their populations unstable.