Transcript:

Today on Animal Fact Files we’re talking about blue tangs. These fish may be known by many other common names including palette surgeonfish, royal blue tang, regal blue tang, Pacific regal blue tang, hippo tang, flagtail surgeonfish, and blue surgeonfish. We’re going to stick with “blue tang” since that seems to be the most common of the common names; but, of course, this still presents issues! The name “blue tang” may be in reference to one of two other fish species - one which can be distinguished by its darker face and the other which lives on the opposite side of the world of today’s subjects. This is why scientific names are so important, y’all.

Blue tangs are Indo-Pacific fish. Blue tangs found outside of this area, such as those found in the Mediterranean Sea, are believed to be individuals released by aquarium owners. We would be remiss not to mention Dory in a blue tang episode. If blue tangs have any common name more common than “blue tang” it’s “the Dory fish.” Many people know the exact fish being referred to if that particular common name is used. Dory’s appearance in Finding Nemo made blue tangs surge in popularity for home aquariums. For a long time, these could only be supplied by wild caught individuals; it wasn’t until 2016 that blue tangs were bred in captivity, and even today many for sale are taken from the wild which raises some concerns for their populations. Currently, however, blue tangs are listed as “least concern.” Blue tangs are also threatened by habitat degradation. These fish live on coral reefs and the waters surrounding them. They are epipelagic meaning they stay in the parts of the ocean where light is able to penetrate. Blue tangs are important to reef systems because the adults eat algae. Algae can choke out a reef if left to overgrow, but blue tangs help to reduce this growth. They can even eat algae growing on sponges! Aside from algae, blue tangs also consume zooplankton. Blue tangs will swim in fast moving currents to catch these tiny animals as they are pushed into the blue tangs’ mouths. This diet can make them bad to eat, though.

Blue tangs are a type of surgeonfish and will travel in loose groups of similar species. They’ll breed throughout the year depending on their location. Male blue tangs may fight with each other over females. They have some gnarly defenses we’ll be discussing a bit further into the episode. Male blue tangs are often larger than the ladies, but on average these fish reach about a foot long at full size. Blue tangs are broadcast spawners meaning they release their gametes, or their eggs and sperm, into the water to be fertilized externally. Each egg has a drop of oil inside it which helps it float in the water. The egg will hatch a day later but the larva doesn’t emerge fully developed; in fact, its heart doesn’t even start beating until a few hours after hatching! It takes blue tang fry just over a month to fully develop, and their sexual maturity isn’t based on age but size. When blue tangs reach about four and three quarters inches in length, they’re ready to begin beeding.

Blue tangs are well known for their bright blue color, but juveniles are actually yellow. Also, the adults can change color! When they’re stressed, blue tangs may become darker; during the breeding season, these fish may become paler; and at night they’ll take on a more violet hue. To defend themselves from attacks, blue tangs have venomous spines on each side of their caudal, or tail, fins. These can be used to smack attackers. Blue tangs may also hide among coral formations, but one of their silliest defense techniques is actually laying down sideways and staying motionless! Predators to blue tangs include larger fish like tuna and grouper. These fish don’t live nearly as long in captivity, but in the wild they may live to be 30 years old!

For more facts on blue tangs check out the links in the description. Thank you to Bard and Gregory for today’s request! Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.