Grade 10 marine and fisheries technology – Fish Morphology and Anatomy Quiz

The operculum is a bony flap that protects delicate gill filaments and, by opening and closing, helps move water over the gills so oxygen can be taken up.

The swim bladder is an internal gas-filled organ that lets fish adjust their buoyancy; by adding or releasing gas they rise or sink without wasting energy swimming.

The lateral line is a sensory organ made of hair cells in canals that sense movement and pressure changes in water, helping fish detect predators, prey and obstacles.

Most teleosts (including common Kenyan species like tilapia) have thin, overlapping cycloid or ctenoid scales. Placoid scales occur in sharks and ganoid in some ancient fishes.

Most fishes have a heart with two principal chambers—an atrium and a ventricle—plus accessory parts; this simple pump sends deoxygenated blood to the gills for oxygenation.

Gill filaments provide a large surface area with thin membranes and blood flow, enabling efficient diffusion of oxygen into the blood and removal of carbon dioxide.

A fusiform body reduces drag and allows sustained high-speed swimming, which is typical of pelagic predators and fast cruising fishes.

The dorsal fin acts like a keel, helping stabilise the fish in the water and preventing unwanted rolling as it swims.

An inferior mouth faces downward and is ideal for picking food off the substrate, such as detritus, algae or small invertebrates on the bottom.

Countershading camouflages fish: from above they blend with the dark depths and from below they match the light from the surface, reducing detection by predators or prey.

Marine bony fish use chloride cells in the gills to actively excrete excess salts they absorb from seawater; kidneys also play a role but gills are key for salt excretion.

Pyloric caeca are finger-like pouches that increase digestive surface area and secrete enzymes, aiding digestion and absorption of nutrients.

Tilapias are oviparous: eggs are laid and fertilised, and in some tilapia species parents may mouthbrood eggs and young, but development begins outside the mother's body.

Red muscle contains more blood and mitochondria, allowing aerobic metabolism for steady swimming; white muscle powers short, rapid bursts.

Many fish use the swim bladder to amplify sounds or produce noises for communication; it can also enhance hearing by transmitting vibrations to the inner ear.

Sharks (cartilaginous fish) often have heterocercal tails with an enlarged upper lobe that helps generate lift; most bony fishes like tilapia have homocercal tails.

A mucus coating covers fish skin; it protects against pathogens, reduces drag in water and helps heal minor injuries.

Gill rakers are comb-like structures that filter out debris or retain plankton/prey during feeding while allowing water to pass over the gills.

Anadromous fish (like salmon) live mostly in the sea but migrate into freshwater to reproduce; the opposite is catadromous (freshwater to sea).

Pectoral fins, located on the sides just behind the gill covers, are used for steering, braking, hovering and precise movements.

The liver plays roles in metabolism, stores lipids (fat), and produces bile which aids in the digestion and absorption of fats.

Teleost fishes have true bony skeletons made of ossified bone; by contrast, sharks and rays have skeletons made mainly of cartilage.

Photophores are light-producing organs used by many deep-water fish for counter-illumination, luring prey, or signaling to other fish.

The oesophagus is a muscular tube that transports swallowed food from the mouth to the stomach for digestion.

The kidneys filter blood to remove nitrogenous wastes and help balance salts and water; gills also excrete some ammonia but kidneys handle internal waste processing.