In the early 1940s Max Pollak spent time in Mexico and Central America, where he evidently spent time diving. He recorded many of his observations in a series of colorful etching/aquatints.
This image,"Tropical Fish I" features a Zebrafish, also known as a "Lionfish", with a rock and fan coral with small red and blue fish, swimming in a clear water. The Lionfish has recently invaded the east coast of North America, the Gulf of Mexico and the Caribbean. Much of this is caused by aquarium releases and climate change.
The Lionfish has few predators and a voracious appetite and have destroyed many of the small fish that live and maintain the health of coral reefs. These reef fish help keep our reefs healthy and if they get eaten in large numbers then the reefs are in danger of getting overgrown in algae. Throw in warmer oceans, pollution, and other stresses on our reefs and you are left with a fragile ecosystem.