B. fenyesi is a small rove beetle ranging from 4.5mm to 6.5mm. They vary from brown, black and gold on their bodies. Their elytra and abdomen are fuzzy and can help distinguish them from other smaller rove beetles. They are one of the most common beetles in the kelp wrack across all beaches. Their diets consist of larval and small adult flies, along with scavenging dead arthropods. They may also predate on smaller rove beetles like T. geniculata. B. fenyesi will use flight to escape when disturbed.