The sea is very much a different place from that we know on land. Although some phyla (main taxonomic groups) have made the transition to the land, such as a primitive fish becoming the origin of amphibians, reptiles, birds and mammals, and a slater-like creature which became the ancestor of the insects, most of nature's experiments in body form have stayed in the sea. Among these, the sponges, anemones and corals are well known. Having had ample time to evolve, some fishes have developed into strange creatures, admirable for their weirdness. In this article we'll have a closer look at them.

The frogfish belongs, with a number of other weird fishes such as the flat-bellied goosefish, the toadfish and the batfish, to the family of Antennariidae (antenna bearers) in the order of Lophiiformes (crestfishes), to which the deepsea anglerfishes also belong.  Often bizarre in form, anglerfishes are also characterised by small gill openings and by limblike pectoral and in some species pelvic fins. The sargassum fish (Histrio histrio) is patterned very much like the sargassum weed in which it lives. It clings to the branches of algae with its prehensile (clutching) pectoral fins as it hunts for prey, which is sucked into the mouth with its powerful jaws and expandable cheeks.  Frogfishes and toadfishes are very rarely encountered by divers although fishermen do catch them from trawls to 100m depth.  See also a news article about this frog fish, on this web site.

f021231: The zebra frogfish, also known as striped anglerfish(Phrynelox zebrinus) sits here perched on its modified breast fins. These fins have developed into little hands, positioned far further back than normal, so that it can balance on them. To complete the confusion, its belly fins are placed further forward than normal, enabling it to walk around on all fours.

f021230: while swimming, the zebra frogfish uses its paws as ailerons. Having no swim bladder, it sinks down to the bottom, but these fins keep it aloft. It swims in a clumsy way, fluttering its whole body. Perhaps for this reason, its fused back fin, which gradually merges into its body, serves for swimming too. Its anal fin is unusually large, also serving as a swim fin.

f021234: not only has it lost its scales, and replaced these by fur during its strange adaptation, but the first spine of its back fin has turned into a fishing lure, with a fleshy flap at its end. Waving the almost transparent spine up and down in a beguiling way, the fleshy end looks like a swimming worm in distress. When a fish attacks, the frogfish suddenly jumps up, assisted by its strong feet, and while opening its cavernous mouth, swallows its hapless victim whole.

The pufferfishes (Tetradontidae) all have cylindrical shapes and are able to puff their bodies up with water. They do so by closing a flap over their gills and gulping water down their mouths. It is so funny seeing them do so. Pufferfishes have sharp bony jaws with which they can exert considerable force. Their skins have no scales. Most pufferfishes are highly poisonous, especially their digestive organs. Although it is possible by a skilled person to remove these organs without spilling their contents, as is a customary in Japan, pufferfishes or any part thereof should not be eaten. Their potent neuro-toxins have caused many deaths of those who challenged this wisdom, and others who were ignorant of it. Like triggerfishes and leatherjackets, pufferfishes do not swim with their tails but with their dorsal and anal fins, which are well set back on their bodies. This gives them the advantage of double propulsion and high maneuverability. Pufferfishes can, with ease, swim forward and backward, stand on their heads or tails, and so on, which allows them to find food where others can't reach.

f024506: the sharp-nosed pufferfish or clown toado (Canthigaster callisternus) is no more than 15cm long, but usually half the size of one's hand. It is cute and intelligent. With its pointed snout and flexible propulsion, it nibbles a bit here and there, often swimming far out into the open sea in search of jellyfish. With its pointed snout, it can pierce the jelly to reach the flavoursome and nutricious gonads inside. This little darling is easy to catch at night when sleeping. Held in one's hand, it then puffs itself up to a perfectly round ball, looking all the more funny and endearing, with only its little tail and pointed nose sticking out. It then waits for a moment of reduced attention, to deflate itself very suddenly, and swim away into the vegetation where it disappears from sight due to its disruptive coloration.

The porcupine fish (Allomysterus jaculiferus) belongs to the family of Diodontidae, which is related to the pufferfishes. Like pufferfish, the porcupine fish can inflate itself, and become a large ball of up to 50cm diameter, with its spiny scales sticking out in all directions. The porcupine fish has a large head with beautiful large eyes, which make it so endearing to meet. When approached carefully, the porcupine fish can be taken in one's hands. When poked a little, it will inflate itself by gulping large gulps of water. Fully inflated it does not feel hard to the touch, but soft and silky, except for its spines. These are in themselves little miracles of adaptation, in the way they consist of four prongs, one of which stands outside the skin. The other three allow the scale to be firmly implanted in the skin, while allowing it to swivel out of harm's way. This arrangement also prevents the fish from being stung by its own spines. Porcupine fishes have cute mouths consisting of strong bony plates with which they can crush shellfish. Their large eyes can rotate freely to look forward like mammals do, and backward as well.

f019612: This porcupine fish was photographed inside a cave where it was resting. About 40cm long, this little fish can inflate itself to a large round football. It has beautiful large eyes, almost child-like. Notice its spines in resting position, laid back along its body, but when fully inflated, they point straight outward. Notice also its swim fins (dorsal and anal) at the rear end. It does not swim with its tail.

Seahorses have evolved an amazing method of getting babies. It took mammals a long path from a fish-like creature, to develop four legs, internal fertilisation and child bearing followed by breast feeding. Seahorses have evolved quite separately, to their own version of internal fertilisation and child bearing. The male has a brood pouch and this distinguishes it from the female who does not have one. When ready to mate, they court one another in a long and affectionate courtship dance, synchronising their body and snout movements. It is fascinating and endearing to watch. Swimming rapidly up and down in the water column, they need about one metre of space, which is not often found inside aquaria. The female then sits on top of the male's inflated pouch and squirts a small quantity of red jelly, containing a few hundred eggs, into its opening. Fanned by two tiny belly fins inside its pouch, the male not only inflates its belly, but spreads the jelly around. Each egg then attaches to the pouch's internal lining, and develops a kind of placenta by which it takes food from the father. Each egg grows a hundred times until a true baby seahorse of 20mm leaves the father's pouch. They immediately rise to the surface to find planktonic animals to feed on. The father is left behind with hundreds of tiny wounds which run the risk of infection. Seahorses have a unique method of catching prey. Their long snouts have only tiny mouths. Their gill covers have developed into muscular bellows with which they can suck fiercely. While also snapping their necks, little shrimps and other crustaceans are swallowed with the sound of a loud click.

f015700: closeup of a female seahorse. Notice her beautiful eyes and small mouth at the end of her snout. Even at this magnification, her breast fins can hardly be seen, behind her bony 'cheeks'.

f003900: a female seahorse (Hippocampus abdmoninalis) found in its natural surroundings, among the flex weed (Carpophyllum flexuosum) in the sheltered waters of an estuary. A seahorse swims by undulating its dorsal fin, assisted by fanning movements of its breast fins, which have moved to just behind its eyes. These fins are quite transparent and invisible, so that its prey does not notice their movement.

f021623: a small male seahorse benefits from the entangled lines caught by wharf pilings. Seahorses are very vulnerable because they cannot swim away rapidly. Their main defense consists of being rather inedible because of their hard skins and little useful content. They are also well camouflaged, adapting their colouration to their surroundings. Notice the smooth belly starting where his bony plates end. Males also develop protrusions on their heads once fully mature. This one is just developing them.

f003929: a male seahorse holds on tight to a root of a mangrove tree, as the tidal current races past him towards the sea. Notice that the animal's large pouch is well filled, a sign of pregnancy. His mate will return to him at regular times, and usually will share the night with him. Seahorses are bonded for life, although they may not be strictly faithful. One thing is for sure, one knows who the father is.

f003324: seahorses are not easy to find in the wild, due to their excellent camouflage and also because they don't move much. Here a seahorse couple rests intimately embracing each other and a branch. Seahorses only like branches of a certain thickness; not too thick and not too thin.