Bluespotted Fantail Ray (Taeniura lymma)

There’s something so graceful and beautiful about rays that I can’t help admiring them. I think it’s the way they move through the water, with their undulating ‘wings’ — they are such marvellous but strange creatures. I’ve written about a few rays before: the manta ray and the giant freshwater stingray, and today I’m going to talk about the bluespotted ribbontail, or fantail, ray.

Bluespotted ribbontail rays live in the Indian and western Pacific Oceans. They are found in shallow coastal waters, rarely venturing beyond 25 meters in depth. Bluespotted rays prefer to live in and around coral reefs and sandy flats, so they have places to hide during the day. The rays will also venture into intertidal zones and tidal pools.


Aren’t these guys amazingly beautiful? Image credit: Jens Petersen via Wikipedia

These stingrays are easily recognized by the bright blue spots that cover their bodies, though they are not the only species of ray known as bluespotted stingrays. They are, however, quite distinctive, as they have more and brighter spots than other species, as well as having two bright blue stripes on their tails. Bluespotted fantail rays do not get overly large, reaching maximum widths of 35 cm. They are oval in shape, with a smooth, yellowish-green disc.

Bluespotted fantail rays are nocturnal, spending the day hidden in caves, shipwrecks, or coral reefs. At night, these guys emerge and head to the shallows, following the high tide into tidal flats in search of tasty meals. They feed on a wide variety of animals, including crabs, shrimp, fish, and sand worms. They detect their prey using electroreceptors, and trap them by pressing their discs into the ocean floor. Once the prey is caught, the rays move around until their meal is directed into their mouths, which are located on the underside of their bodies. Bluespotted rays have 15-24 rows of teeth arranged into plates, which can easily crush the shells of molluscs.


A close up of a bluespotted ray’s eyes, which makes it look pretty creepy. Image credit: Nick Hobgood via Wikipedia

Bluespotted rays themselves are targeted as prey; both hammerhead sharks and bottlenose dolphins are known to feed on these rays. When threatened, bluespotted rays prefer to run away, swimming in zigzags to try and confuse predators. These rays have another method of defence, however — they have lovely venomous spines at the tips of their tails, which can deliver a nasty sting to anyone foolish enough to get close to them. Hammerhead sharks get around this by using their hammer-shaped heads to pin the stingrays down while they eat them.

Bluespotted rays mate in the spring and summer, when males start to follow females around. They eventually start nipping at the females’ discs, and then hold on while the pair copulate. The exact gestation period of bluespotted fantails is uncertain, but after four to twelve months females give birth to up to seven pups, which look like miniature versions of their parents.


A quick sketch of a bluespotted fantail ray.

Bluespotted fantail rays are popular in home aquaria, in spite of their dangerous spines. They are also very difficult to keep in captivity, with many refusing to eat or dying for unknown reasons. But people still try and keep them for some reason, and the rays are also suffering from degradation of their natural habitat. They are still fairly abundant in the wild, but have been assessed as Near Threatened by the International Union for Conservation of Nature (IUCN). Hopefully these beautiful creatures can stick around for a while.

Cover image credit: Jon Hanson via Wikipedia

Blue Tang (Paracanthurus hepatus)

Has anyone seen Finding Dory yet? I haven’t, but when I was trying to think of a fish to write about this morning, I saw a post online about the movie. Problem solved! Today we’ll talk about the blue tang, also known by a myriad of other names, including regal tang, palette surgeonfish, hippo tang, and doctorfish.

Blue tangs are marine fish, and live in the Indo-Pacific Ocean. They live in and around coral reefs, in tropical and sub-tropical areas, where temperatures stay between 24 and 26 degrees Celsius. They are found in reefs along the coast of East Africa, Japan, Samoa, New Caledonia and the Great Barrier Reef.

You have probably seen blue tang fish; they are very recognizable, with bright blue bodies, black stripes, and yellow fins. They can get to be 30 cm long, with males being larger than females. Young blue tangs are more yellow than blue, and darken to full blue as they mature.


A very pretty blue tang. Image source: Wikipedia

Blue tangs are targets for some marine predators, such as tuna and tiger groupers. They will often school together in reefs, sticking close to other blue tangs for protection. This is especially effective because each blue tang possesses a razor sharp caudal spine. These can be extended when the fish feel threatened, meaning that a predator swimming into a school of blue tangs would have to deal with a bunch of fish, all with super sharp spines. Not a smart choice.

The tangs also have less aggressive methods of dodging predators. They can change their colour, making themselves darker or even semi-transparent to hide themselves in the reefs. They will also play dead, lying still until the predator moves on.

Blue Tang1

A small school of blue tangs. Image source

Blue tangs will either breed in groups or in pairs. In both cases, they swim towards the surface before releasing eggs and sperm into the water. This is thought to help with dispersing and mixing the gametes. The eggs will hatch in the next 24-28 hours, and grow quite quickly. They become mature at 11-13 cm in length.

Blue tangs are very pretty fish, and Dory is a great character. But they are quite fragile in captivity, and are not known to breed in tanks, which means all blue tangs are wild caught. So I definitely wouldn’t want one as a pet, though I’ll certainly enjoy watching Finding Dory!

Cover image source

Arrow Crab (Stenorhynchus seticornis)

As regular readers of this blog probably know, I’m pretty terrified of spiders. Oddly enough, though, I have no problems at all with another group of eight-legged creatures. Crabs have never frightened me the same way spiders do, and there are three reasons I can think of why this is.

This first is that crabs don’t spin webs, so there’s no chance you’ll walk into a gross sticky web. The second is that unless your house is on the seashore, there’s a pretty slim chance you’ll stumble across across a crab in your house — you can basically choose whether or not you want to see crabs, by simply avoiding the beach. No such luck with spiders. And thirdly, the way crabs and spiders move is very different. Moving siders are enough to make me run screaming in the opposite direction, but I’ll likely follow a moving crab and probably try and pick it up.

Even if I was afraid of crabs, I probably wouldn’t be too scared of today’s animal, the arrow crab, because it really doesn’t look much like a crab at all. Arrow crabs are found in coral reefs in the Atlantic Ocean, at depths of 10 to 30 m. They are known to occur in the west from North Carolina to Brazil, and in the east around Cape Verde.

Stenorhynchus Seticornis

These crabs look so funny! Image source

Arrow crabs don’t grow very large, reaching lengths of only 3 to 6 cm. This only includes the crabs’ bodies, however, and not their legs, which are extremely long and thin, and can get to be 10 cm long. The most distinctive feature of arrow crabs is their long, pointed head, that has cool serrated edges. These crabs can be a lot of different colours, from golden to cream to yellow or brown, with black or iridescent stripes. Their claws are a beautiful bright blue.

Arrow crabs are active mostly at night, hiding under rocks and sea fans. They come out after dark to feed, and are quite territorial, especially with members of their own species. Arrow crabs scavenge whatever they can find, but will also hunt feather duster worms and other small coral animals.


A nice image showing the arrow crab’s blue feet. Image source

Reproduction in arrow crabs isn’t particularly exciting. Male crabs grab females and deposit spermatophores onto their abdomens, which the females can use to fertilize their eggs. The females carry their eggs on their abdomens until they hatch, at which point the larval crabs are on their own. The young crabs swim to the ocean surface, where they feed on plankton until they moult into their adult forms.

Arrow crabs are quite common in aquaria, and are used to control bristle worm populations. They are pretty neat looking, so I can definitely see the appeal of having one. Still, I’ve never had much of a desire to have an aquarium, so I don’t think I’ll be getting an arrow crab anytime soon.

Cover image credit: Nick Hobgood via Wikipedia

Frogfish (family Antennariidae)

I was convinced I had to blog about these fish as soon as I saw their name. It immediately conjured images of strange frog-fish hybrids, which of course would never happen. It turns out that the name frogfish is one of the least interesting things about these guys. Frogfish are actually anglerfish, and make up the family Antennariidae.

Frogfish are found pretty much anywhere in tropical or subtropical waters, in both oceans and seas. The most dense area of frogfish species is around Indonesia, where nine different species were found in a single strait. Frogfish like to live in and around coral reefs, and rarely stray deeper than 100 m.

Describing frogfish as a group is fairly difficult, because they are so varied in appearance. They are generally stout, looking more like irregular round balls than fish. They range in size from 2.5 to 38 cm long. Many species are covered in spinules, which can take the form of bumps or spine-like projections. Colours in frogfish can differ both between and within species, and can include white, yellow, red, green, and black.


A well-disguised frogfish. You can barely even tell that this is an animal. Image credit: Stephen Childs via Wikipedia

Frogfish are so different in appearance because they are masters of camouflage. These fish don’t have scales or any other form of protection, so they rely on their disguises to keep them safe from predators. Frogfish successfully imitate coral and stones, sponges, sea urchins, and seaweed. Sea slugs have been so fooled by frogfish camouflage that they have crawled on them, completely unaware that they were actually moving on top of living fish.

Another excellently disguised part of frogfish is their escas, or lures. These can take the form of a number of different ‘creatures’, including fish, shrimp, and worms. Frogfish use the lures to entice prey into approaching to a fatal distance. They hunt a variety of prey, such as crustaceans, fish, and other frogfish. Frogfish can expand their stomachs, allowing them to eat animals twice their size. Frogfish will wave their lures around, mimicking the movements of the animal the lure is disguised as. When the prey gets close enough, the frogfish open their jaws in a rapid motion, which sucks the prey inside. This action occurs extremely quickly, in as little six milliseconds.


A crazy-looking frogfish with a nice fat worm as a lure. Image credit: Jens Petersen via Wikipedia

This is about the only movement frogfish do quickly. The rest of the time, they walk ponderously across the ocean floor, if they move at all. Though frogfish can swim, they prefer to walk along the ocean floor, either in an ambling walk or a kind of gallop. If given a choice, however, they would choose not to move, and lie still waiting for prey to approach.

Though I’ve written about a number of camouflage experts, I think frogfish are probably some of the best around. It’s a shame they aren’t actually a cross between frogs and fish though, like I initially thought. They’re still super cool though!

Cover image credit: Tanaka Juuyou via Wikipedia

Merten’s Carpet Anemone (Stichodactyla mertensii)

I don’t recall ever being stung by a sea anemone, but I’ve heard it can be pretty nasty. Still, anemones are fascinating creatures, and they look quite cool with all their tentacles waving about with the currents. The only anemone I’ve written about was the Cloak Anemone, which forms a partnership with hermit crabs. Today’s anemone is an entirely different type, choosing to live a more sedentary life.

Rocky, coral areas are the preferred habitat for Merten’s carpet anemones, which live in tropical waters in the Indo-Pacific Oceans. They don’t like to live in very deep water, usually hanging out around depths of one to twenty metres. Merten’s anemones like rocky areas because these allow the anemones to hide their bodies in crevices, only exposing their mouths to the dangers of the open ocean.

A really beautiful picture of a Merten's anemone and some fishes. Image source:

A really beautiful picture of a Merten’s anemone and some fishes.
Image source:

Merten’s carpet anemones are the largest sea anemones in the world. They can reach staggering proportions of over one metre in diameter. That’s a little ridiculous for a sea anemone. Other than their size, Merten’s anemones are a bit boring, having no bright fun colours that other anemones flaunt. I guess these guys decided to forgo colourful creativity in favour of getting really, really large. They are different shades of green, yellow or cream.

The tentacles of Merten’s anemones are also fairly unimpressive. They are relatively short, only being about a centimetre or two long. The anemones use these tentacles for protection from predators. I know, it’s weird that things would want to eat an anemone, but there are animals that try. Predators of Merten’s carpet anemones include other anemones, sea stars, and some types of fish.

Here's a Merten's anemone all folded up. Image source: Distribution / Background

Here’s a Merten’s anemone all folded up.
Image source: Distribution / Background

These sea anemones can be aggressive, but they also share their large bodies with a number of different organisms. Some of the most visible of them are anemonefish and damselfish, which hide in the anemones’ tentacles for protection. Other, less obvious partners are the symbiotic zooxanthellae that the anemones require to survive. These algae provide the anemones with most of their food, and in exchange are protected by the anemones’ tentacles.

Some anemones look really neat, but they are a little terrifying thanks to all those nasty tentacles they have. I cannot even imagine seeing a meter-wide anemone. I think something like that could haunt my dreams, so it’s a good thing I have no intention of diving in any ocean, let alone the Indo-Pacific.

Cover image source: Brocken Inaglory via Wikipedia 

Reef Stonefish (Synanceia verrucosa)

I like writing about venomous creatures. Animals that rely on deadly toxins rather than large claws or sharp teeth are really cool. I do, however, value my health rather highly, and so try to avoid venomous animals as much as possible. So I’ll keep writing about them, but I’ll never go to Australia.

The reef stonefish is the most venomous fish in the world. They belong to the stonefish family, which is confusing, since the reef stonefish is often just called the ‘stonefish’. So for the rest of this post, when I use stonefish, I’m referring specifically to the reef stonefish.

Reef stonefish are fairly widespread, living in tropical waters in the Indian and Pacific Oceans. Stonefish are typically found in shallow areas, specifically in and around rocky habitats. Their favourite places are coral reefs.

See how easy it would be to mistake one for a rock? Nasty critters, aren't they? Image source:

See how easy it would be to mistake one for a rock? Nasty critters, aren’t they?
Image source:

This is a problem for swimmers, who may step on the fish, giving themselves a nasty sting. The stonefish’s name comes from its habit of posing as a rock, which means that the chances of someone stepping on one are that much greater. The brown and grey colouring of stonefish helps them blend in. They usually reach sizes of 30 to 40 cm, though some can get to be over 51 cm long. The spines on the back of the stonefish are what transmit the fish’s venom, so watch out for those!

These spines not only have two venom sacs each, they are very sharp and quite strong. Stonefish spines can go through boot soles, so don’t think you’re safe just because you’re wearing shoes. If you do get stung, be prepared for a lot of pain, paralysis, and tissue death. Stonefish stings can be fatal to young and old people, but stings usually don’t kill healthy adults. There can be permanent nerve damage to the affected area though, so try to avoid stepping on a stonefish.

Maybe some people think stonefish are pretty? Image credit: Richard Ling, via Wikipedia

Maybe some people think stonefish are pretty?
Image credit: Richard Ling, via Wikipedia

Stonefish are sometimes sold as pets for aquaria — which I’m not sure I would want if I had an aquarium. They are fairly funny looking, but having such a venomous creature near me would make me nervous. What if I stepped on one while I was cleaning the tank?

Cover image source: Wikipedia