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Flagtail

Genus Kuhlia

Fish

Range: Indo-Pacific marine and freshwaters

Habitat: Reefs, coastal estuaries, streams, rivers, and more

Size: Up to 18 inches (46 cm) though on average only half this

Diet: Crustaceans, fish, insects, flowers, fruit, and more

Threats: Construction of dams and loss of habit

Lifespan: Unknown

Transcript:


Today on Animal Fact Files we’re discussing flagtails. Flagtails are fish that are part of the perch family. In fact, some of their other common names reflect this, one example being the flagtail species also known as the jungle perch. They get their name flagtail because of obvious bars and spots that appear on their caudal fins: their tails resemble little banded flags! Flagtails superficially look similar to freshwater sunfishes. They have a deep notch in their dorsal fin so it almost looks like they have two back fins instead of one. This is similar to the wavy dorsal fin of sunfishes. 


There are other fish that have the name flagtail but aren't related to the fish described in this episode. While they also have a colorful, banded tail, they're pretty easy to tell apart just by looking at their dorsal fin. See how this flag-tail has a long, pointed dorsal fin? This particular flagtail lives in the Amazon River basin. The flagtails that are part of the perch family swim in both fresh and saltwater around coasts of the Indo-Pacific region. They're found as far into the Pacific as the Hawaiian islands!


Most flagtails swim no deeper than 60 feet (18 m) below the waves. They live on reefs but they also inhabit brackish water estuaries and some species swim upstream into flowing freshwater rivers, so they can tolerate a wide range of salinity. One of the threats they face is the introduction of dams across the rivers and streams they frequent, cutting off their access to vital habitats. Flagtails are also caught by humans and eaten either fresh or dried out and salted. It's likely they're also taken by larger fish, although flagtails at their full size can get pretty big.


Some flagtails can reach more than a foot (30.5 cm) long while others average a few inches shorter. They hunt at night, seeking out all sorts of food. Flagtails eat crustaceans and smaller fish, but they also eat insect larvae and frogs. This is especially worth noting for flagtails native to Australia where their presence can help reduce invasive cane toad populations. The fish eat cane toad tadpoles! Flagtails also eat adult insects as well as fruit and flowers that fall into the water. It's not uncommon for flagtails to eat these meals directly from the water's surface.


In general, flagtails prefer to stay closer to the waves than down towards the water's bottom. They often form tight shoals with multiple members as they move about. They're described as movement driven fishes and likely don't ever stay in one place for too long. There's little known about their breeding habits and lifecycle. Juveniles can sometimes be found in tidepools where they have some protection for larger predators who can't manage in these shallow habitats. It's likely these ever-moving fish migrate to specific spawning grounds and it's believed that females lay multiple clutches of eggs during the breeding season.  


For more facts on flagtails, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!

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