Diurnal zooplanktivores from various coral reef fish families, such as Creole wrasses, exhibit similar morphological characteristics that benefit them when it comes to feeding on minute animals in the water. Many zooplanktivores have small, highly protrusible, upturned mouths with small (or no) teeth in the jaws. The mouth size and position near the end of the head allows the fish to see its small target with both eyes, thus providing better depth perception and greater feeding accuracy.
Diurnal planktivores also tend to have more and larger gill-rakers that prevent small prey items from escaping through the gill opening. They also tend to possess body types that enable them to get back to the reef very quickly. For example, a lunate (moon-shaped) tail and a more fusiform (torpedo-shaped) body are indicative of superior speed that enables an animal to elude predators more effectively.
Creole wrasses (Clepticus spp.) possess most of the characteristics described. In many ways, they are more similar in general appearance to anthias (Pseudanthias), chromis damsels (Chromis) or swallowtail angelfish (Genicanthus) — all of which feed on zooplankton — than to other wrasses.
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