Why do these fish look like they’re spouting puffs of magic dust out of their mouths? The tiny crustaceans (1 millimetre-long crustacean called an ostracod) that these transparent fish try to eat light them up, causing the fish to be at risk of predation themselves, so they spit them out!

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Shown above are vampire fish caught in Corona Falls, Guyana. Also called payara by locals, these Amazon Basin predators feed on other fish, especially piranhas, which they impale on their long fangs.

Gnathiids are a family of isopod crustaceans whose larvae feed on the blood of fish. During the day, infected parrotfish seek out cleaner fish to consume the parasites; however, at night they are relatively vulnerable to attack. Parrotfish overcome this vulnerability by secreting a mucus cocoon before sleeping which envelopes their bodies with a protective biopolymer that functions similar to a mosquito net. The mucus is secreted from large glands in the gill cavity and is composed of small glycoproteins which are extensively cross-linked through pyrosulfate bonds. This exopolymer net allows small molecules to permeate but prevents the parasitic gnathiids from entering. The process is thought to involve a combination of blocking odorants ...

The hairy frogfish (Antennarius striatus) is a marine fish with spines resembling strands of hair - and it can change color. This small fish grows up to 22 cm (8.7 in) long, and has a rounded, extensible body. Its large mouth is forwardly extensible, allowing it to swallow prey as large as itself! The coloring of its body is extremely variable because individual fish tend to match their living environments.

Frogfishes have the capacity to change coloration and pigment pattern, taking only a few weeks to adapt. The dominant coloration varies from yellow to brownish-orange, passing through a range of shades, but it can also be green, gray, brown, almost white, or even completely black without any pattern. Body and fins can be marked with roug ...

There's more to studying than simply memorization and practice. It turns out that your diet also plays a pivotal role in recalling key bits of information, while keeping you energized and focused in the process. We're not talking about those scam-ridden supplements that promise a boost in brain power, but simple natural foods such as milk, nuts, seeds, rice, and oats.

The nutrients found in these items help your study efforts by releasing natural memory enhancers called CCKs ( cholecystokinin). When CCK crosses the blood-brain barrier, it acts as a neurotransmitter associated with memory. Studies have shown that learning and memory processes are severely damaged (in rats) that genetically do not respond to the presence of CCK. And in people ...

The arapaima (Arapaima gigas) is one of the biggest freshwater fish on the planet and has evolved a multi-layer defence against the piranha. Its scales have an ultra-tough outer shell, which promotes tooth fracture at the point of penetration. The scales are also a corrugated shape, which deflect pressure to overlapping layers of collagen underneath.

The angry-looking deep sea angler fish has a right to be cranky. It is quite possibly the ugliest animal on the planet, and it lives in what is easily Earth's most inhospitable habitat: the lonely, lightless bottom of the sea.

There are more than 200 species of anglerfish, most of which live in the murky depths of the Atlantic and Antarctic oceans, up to a mile below the surface, although some live in shallow, tropical environments. Generally dark gray to dark brown in color, they have huge heads and enormous crescent-shaped mouths filled with sharp, translucent teeth. Some angler fish can be quite large, reaching 3.3 feet (1 meter) in length. Most however are significantly smaller, often less than a foot.

Their mouths are so big and their bo ...

Herons also have surprising intellectual abilities; they can use bread to catch fish! It is thought that the birds learn the technique from watching fisherman throw baited hooks and tourists tossing bread to attract fish.