The animals on the cover of Learning MySQL and MariaDB are banded angelfish (Apolemichthys arcuatus), so named for the black band that runs on either side of each fish’s body from the eye to its tail. The banded angelfish’s laterally svelte body and soft dorsal fin are typical of the other marine angelfish in its Pomacanthidae family. Known also as bandit angelfish, members of this species inhabit the caves and ledges of rocky reefs found at moderate depths in the waters around Hawaii and the Johnson Atoll.
The behavior of marine angelfish differs widely between species, and members of the Pomacanthidae family are as likely to form monogamous pairs as gather in groups of one male marine angelfish to several females. As protogynous hermaphrodites, marine angelfish are capable of changing sex from female to male when the single male member of such a group dies or is otherwise removed.
Sponges constitute the bulk of the banded angelfish’s diet, though it also eats algae and certain invertebrates. Difficulty replicating the banded angelfish’s diet is a major impediment to the efforts of collectors who would keep banded angelfish in aquaria. Nevertheless, commercial aquarium fishermen appear to have thinned the population at normal diving depths on certain reefs.
Many of the animals on O’Reilly covers are endangered; all of them are important to the world. To learn more about how you can help, go to animals.oreilly.com.
The cover image is from Cuvier’s Animals. The cover fonts are URW Typewriter and Guardian Sans. The text font is Adobe Minion Pro; the heading font is Adobe Myriad Condensed; and the code font is Dalton Maag’s Ubuntu Mono.