Carniadactylus was similar in appearance and anatomy to its close relative Eudimorphodon, though it was significantly smaller. Like Eudimorphodon, it is notable for its complex multi-cusped teeth. Despite their similarities, the size difference between these two pterosaurs likely meant that they occupied different niches and relied on different food sources. This is supported by studies of their teeth. While similar in construction, the teeth of Carniadactylus show little to no wear, unlike the larger, fish-eating Eudimorphodon, which may have been able to chew its food. The smaller Carniadactylus probably fed on smaller, soft-bodied prey like worms and insect larvae.