How to Identify a Bicolor Damselfish

Video Transcript

"The marine organism that we are going to identify now is the bicolor damselfish. One of the most aggressive fish on the coral reef, is the damselfish. And, the bicolor damselfish is one of the most common of the damselfish species. A relatively tiny fish, usually only two to three inches long, although they can reach a maximum size of four inches. The bicolor damselfish will defend its territory very aggressively. Their territory generally only covers a small area, for example a small coral head in the sand, but they will attack anything that gets to close to it. I've seen bicolor damselfish chased fish more than twice their size out of their territory. I'm just glad they don't get any larger because if they did, I will be a lot more afraid of them then anything else in the ocean. Bicolor damselfish are usually easy to identify. The front half of their body is usually dark and the back half is white. Although the line of demarcation between the light area and the dark area is usually above mid-body, it can shift forward or backward on some specimens. In fact, there have been reports, although I haven't seen this myself, that some bicolor damselfish have a reversed color scheme. Light front and dark back. Bicolor damselfish may also have a tail that's clear or it may have a blueish or yellowish cast. Bicolor damselfish are very common throughout the Caribbean and Florida Keys. They can be found at depths ranging from a few feet to depths well beyond safe diving limits for recreational scuba divers. Although they are most commonly found in depths of less than eighty feet. They have a relatively small territory that they patrol and rarely rise more than a few inches above the safety of their patch reef or coral head. If they feel threatened, they will quickly duck into a hole in the reef, but will fairly quickly re-emerged. Bicolor damselfish feed primarily on algae and they tend to maintain their own personal algae patch in their territory. But, bicolor damselfish also reportedly feed on various worms, hydroids, zoo plankton and tunicates. Bicolor damselfish exists as separate male and female specimens. Although their color patterns do not differ. Eggs are laid by the female on the bottom of the reef, and then the male swims over them to fertilize them. Once fertilized, the male bicolor damselfish guards the eggs until they hatched, and will be more aggressive than usual in protecting the area around the eggs. Once hatched, they are on their own and quickly take on the color pattern of the adults and stake a claim on their own coral head. That's the bicolor damselfish."