Range: Coastal waters of East Africa, India, Indonesia, and Australia Habitat: Fast-moving, shallow waters Size: About 7.5 inches (19.05cm) long Diet: Phytoplankton Threats: Crustaceans and more Life span: Up to one decade

Transcript:

Today on Animal Fact Files we’ll be talking about sea apples. For more facts on other animals don’t forget to hit that subscribe button! Sea apples were requested by YouTube user Rovfulg (I hope I’m pronouncing that correctly!). Thank you for the suggestion.

Sea apples are sea cucumbers that belong to the Paracucumaria and Pseudocolochirus genera. There are a few different species of sea apples, and these are largely based on where they’re found in the wild. Sea apples are strictly a marine species meaning they are only found in saltwater. They hang out in depths of about 32 feet (10 meters) which is the general range of coral species, as well. Sea apples live in the Pacific ocean along the coasts of East Africa, India, Indonesia, and Australia and seem to favor spots that position them in heavy currents as this allows them the best access to their food. They are filter feeders and thus depend on fasting moving, food-filled water to survive.

Sea apples almost exclusively eat phytoplankton which are otherwise known as microalgae. This is an appropriate name as phytoplankton are extremely small averaging less than a millimeter in length. Just look at a ruler to see how small really that is! The way sea apples gather the microalgae is by extending their tentacles into a fast current of water and catching the microalgae on their sticky, mucus-covered limbs which they then lick off one tentacle at a time - kind of like we would if we stick our finger in a jar of peanut butter.

Phytoplankton are too small to swim against the current so they are at the mercy of the water in which they live. This is why sea apples seek out places with fast currents - more moving water means more food to collect. Based on the sea apple’s body structure it might seem that they are immobile but they can actually move, albeit slowly, to these optimal food gathering locations. Sea apples tend to catch their food at night when they’re less at risk of being eaten themselves. Of course, they have some defenses against would-be predators.

The easiest targets on a sea apple are it’s aforementioned tentacles. These can be broken off by fish and crustaceans looking for a simple meal. To counteract this, sea apples only release their tentacles while eating. If still under attack sea apples have two other means of dispelling advances. One you’ve probably heard of and it involves them expelling their organs from their body. Accompanied with this they can also release a toxic substance called holothurin which can cause fatality to assailants. Of course, this may not be the most comfortable of defenses so, on the flip side, sea apples can also suck in large amounts of sea water to inflate to nearly double their original size. Like this, they are able to be picked up by water currents and carried to a safer location.

Speaking of double their original size, sea apples are typically about 7.5 inches (19.05cm) long. They’re kind of squat and sausage shaped when relaxed and look like an inflated balloon when in that water-filled defense mode. Sea apples get their name from their vibrant colors that often come in shades of bright red and violet. Their tentacles can appear bright yellow as well as white and soft shades of lilac. And, of course, colors vary among the different species. Their colors are what make them attractive to aquarium enthusiasts but their general complex husbandry requirements make them considered “expert only” aquarium additions. In the wild they may live longer than a decade but many captive kept individuals die before they reach even three years of age.

For more facts on sea apples, take a look at the links in the description. Let us know what you think about sea apples in the comments. Thank you so much for watching and be sure to give a thumbs up for more Animal Fact Files.