Ichthyology – Study of Fishes MCQs
Part 1 — Ichthyology MCQs (Q1–Q25)
Q1. Ichthyology is the study of:
A. Amphibians
• That’s herpetology (amphibian part).
B. Fishes ✅
• Ichthys = fish; ology = study.
C. Reptiles
• Herpetology.
D. Marine mammals
• Marine mammalogy, not ichthyology.
Q2. Most fishes respire primarily using:
A. Lungs
• Only some (lungfish) have lungs.
B. Skin
• Minor role in most fishes.
C. Gills ✅
• Lamellae extract O₂ from water.
D. Tracheae
• Absent in fishes.
Q3. Countercurrent exchange in gills:
A. Mixes blood and water directly
• They never mix.
B. Keeps blood flowing opposite to water to maximize O₂ diffusion ✅
• Maintains gradient along the lamella.
C. Heats the water
• Not its purpose.
D. Works only in freshwater
• Occurs in both fresh/marine species.
Q4. The typical fish heart has:
A. 4 chambers like mammals
• Not in fishes.
B. 3 chambers like amphibians
• Not fishes.
C. 2 main pumping chambers (atrium + ventricle) ✅
• With sinus venosus & bulbus/conus arteriosus assisting.
D. 1 chamber only
• Incorrect.
Q5. The lateral line detects:
A. Light intensity
• Eyes do that.
B. Water movements/vibrations via neuromasts ✅
• Key for schooling and prey/predator detection.
C. Chemical odors
• Olfactory rosettes.
D. Electric fields
• Electroreceptors do this.
Q6. Ampullae of Lorenzini in sharks/rays sense:
A. Sound waves
• Detected by inner ear/lateral line.
B. Weak electric fields (electroreception) ✅
• Useful in prey detection/navigation.
C. Salinity
• Not their role.
D. Pressure only
• Detected by other mechanoreceptors.
Q7. Buoyancy in most bony fishes (teleosts) is aided by:
A. Heavy skeletons
• Would sink them.
B. Swim bladder ✅
• Gas-filled organ adjusts buoyancy.
C. Enlarged liver oil
• That’s typical of sharks.
D. Air stored in stomach
• Not regulated for buoyancy.
Q8. Elasmobranchs (sharks & rays) maintain buoyancy mainly by:
A. Swim bladder
• Absent in elasmobranchs.
B. Large oil-rich liver + dynamic lift from fins ✅
• Squalene-rich liver reduces density.
C. Hollow bones
• Not fish feature.
D. Lung respiration
• No lungs.
Q9. Scales of most modern bony fishes are:
A. Placoid
• Sharks/rays.
B. Ganoid
• Primitive groups (gars).
C. Cycloid/ctenoid ✅
• Thin, flexible teleost scales.
D. Scutes only
• Bony plates in some species.
Q10. Anadromous fishes are those that:
A. Live in rivers and breed in sea
• That’s catadromous.
B. Live mostly in sea but migrate to freshwater to spawn ✅
• Example: salmon.
C. Live only in lakes
• Not migratory definition.
D. Are entirely marine
• Not about migration.
Q11. Catadromous fishes (e.g., eels) typically:
A. Spawn in rivers
• Opposite.
B. Spawn in the sea, grow in freshwater ✅
• European eel spawns in Sargasso Sea.
C. Never migrate
• They migrate vast distances.
D. Spawn in lakes only
• Not defining.
Q12. Marine teleosts maintain osmotic balance by:
A. Producing copious dilute urine
• Freshwater strategy.
B. Drinking seawater and excreting excess salts via gills (Cl⁻ cells) ✅
• Kidney produces small volumes.
C. Stopping ion transport
• Impossible.
D. Storing salt in bones
• Not a mechanism.
Q13. Freshwater teleosts osmoregulate by:
A. Drinking a lot
• They generally do not.
B. Excreting large amounts of dilute urine; active ion uptake at gills ✅
• Replace lost salts via transporters.
C. Excreting salts across gills
• Marine strategy.
D. Becoming isosmotic
• They’re hyperosmotic to water.
Q14. Primary nitrogenous waste in most fishes is:
A. Uric acid
• Birds/reptiles.
B. Urea
• Sharks/CO elasmobranchs (ureotelic); some teleosts under stress.
C. Ammonia (ammonotelic) ✅
• Diffuses across gills; water abundant.
D. Creatinine
• Minor.
Q15. The operculum in teleosts:
A. Is a jawbone
• No.
B. Covers & protects the gills; aids in pumping water ✅
• Bony flap over branchial chamber.
C. Stores food
• Not its function.
D. Detects vibrations
• Lateral line does.
Q16. Which pair is correct?
A. Chondrichthyes — bony skeleton
• Cartilaginous, not bony.
B. Osteichthyes — bony fishes ✅
• Teleosts are Osteichthyes.
C. Agnatha — jawed fishes
• Agnathans are jawless (lampreys/hagfish).
D. Elasmobranchii — lungfish
• Lungfish are sarcopterygians.
Q17. Sarcopterygians are:
A. Cartilaginous fishes
• No.
B. Lobe-finned fishes (coelacanths & lungfishes) ✅
• Ancestors of tetrapods.
C. Ray-finned teleosts
• Actinopterygians.
D. Jawless fishes
• Agnatha.
Q18. Electric organs evolved independently in several fishes to:
A. Produce light
• Photophores do that.
B. Generate electric fields for predation/defense/navigation ✅
• Electric eel, torpedo ray, elephantfish.
C. Regulate temperature
• Not function.
D. Digest prey externally
• No.
Q19. Deep-sea fishes commonly show:
A. High calcified skeletons
• Often reduced ossification.
B. Bioluminescence via photophores ✅
• For prey attraction/camouflage (counterillumination).
C. Lungs for air breathing
• Absent.
D. Bright pigment for photosynthesis
• No light for photosynthesis.
Q20. The function of gill rakers is to:
A. Exchange gases
• Gill filaments/lamellae do that.
B. Filter food/retain prey; protect delicate filaments ✅
• Especially in planktivores (herring).
C. Pump water
• Opercular/pump action.
D. Secrete mucus only
• Goblet cells do.
Q21. In many teleosts, otoliths are used to:
A. Store fat
• No.
B. Sense balance/hearing; also used to age fish from growth rings ✅
• Calcium carbonate ear stones.
C. Oxygen transport
• Hemoglobin carries O₂.
D. Produce sound
• Some drum muscles to swim bladder.
Q22. The Weberian apparatus links:
A. Gills to mouth
• No.
B. Swim bladder to inner ear to enhance hearing (Ostariophysi) ✅
• In carps, catfish, minnows.
C. Lateral line to brain
• Not this term.
D. Heart to operculum
• No.
Q23. Viviparity (live-bearing) in fishes occurs in:
A. Only sharks
• Also in some teleosts.
B. Only teleosts
• Also in many sharks/rays.
C. Both elasmobranchs (sharks/rays) and some teleosts (e.g., guppy, molly) ✅
• Multiple modes: ovoviviparity, placental viviparity.
D. Never in marine fishes
• Many marine viviparous sharks.
Q24. “Ich” (white spot disease) of aquaculture is caused by:
A. Bacteria
• Different diseases.
B. Virus
• Not ich.
C. Protozoan Ichthyophthirius multifiliis ✅
• White cysts on skin/gills; major hatchery issue.
D. Fungus
• Saprolegnia causes “fungal” patches.
Q25. A key indicator of fish freshness is:
A. Sunken, cloudy eyes
• Sign of spoilage.
B. Bright, bulging eyes; firm flesh; red gills ✅
• High quality/oxygenated tissues.
C. Strong fishy odor
• Spoilage amines.
D. Soft, mushy texture
• Degraded proteins.
Part 2 — Ichthyology MCQs (Q26–Q50)
Q26. The primary function of caudal (tail) fin is:
A. Stability
• More for dorsal/anal fins.
B. Propulsion (forward thrust in swimming) ✅
• Tail fin provides main thrust.
C. Steering
• Pectoral fins help steer.
D. Respiration
• Gills, not fins.
Q27. The pectoral fins in fishes mainly help in:
A. Oxygen intake
• Gills, not fins.
B. Steering, balance, braking, sometimes lift ✅
• Especially in slow swimmers.
C. Food collection
• Not their role.
D. Producing sounds
• Indirect in some catfish, but not general.
Q28. Lunate caudal fins are typical of:
A. Bottom dwellers
• Not built for speed.
B. Fast, sustained swimmers like tuna, mackerel ✅
• High-aspect-ratio fin reduces drag.
C. Eels
• Long ribbon-like tails.
D. Frogs
• Amphibians, not fishes.
Q29. Anguilliform swimming involves:
A. Only tail tip undulations
• That’s carangiform.
B. Whole body undulates like in eels ✅
• Flexible body, slow but maneuverable.
C. Only pectoral fins
• Labriform swimmers (wrasses).
D. No body movement
• Impossible.
Q30. Carangiform locomotion is characteristic of:
A. Eels
• Anguilliform.
B. Jacks, mackerel (posterior half of body undulates) ✅
• Efficient, faster swimming.
C. Seahorses
• Move by dorsal fin.
D. Rays
• Undulate pectoral fins.
Q31. Osteichthyes reproduction is usually:
A. Internal with copulation
• Rare in teleosts.
B. External fertilization (spawning eggs & sperm in water) ✅
• Most common strategy.
C. Viviparity always
• Only in some species.
D. Parthenogenesis only
• Very rare.
Q32. Which fishes are known for male parental care?
A. Salmon
• Die after spawning.
B. Mouthbrooding cichlids, sticklebacks, seahorses ✅
• Males incubate/fan eggs or carry young.
C. Sharks
• Mostly no care.
D. Eels
• No care.
Q33. Male pregnancy occurs in:
A. Frogs
• Amphibians, not fishes.
B. Seahorses and pipefish (family Syngnathidae) ✅
• Males brood eggs in pouch.
C. Catfish
• Mouthbrooders, not pregnancy.
D. Salmon
• No parental care.
Q34. The hormone controlling smoltification in salmon (prep for seawater life) is:
A. Insulin
• Not key.
B. Cortisol & growth hormone (seawater adaptation) ✅
• Modify ion transport, osmoregulation.
C. Thyroxine only
• Important in metamorphosis but not smoltification.
D. Estrogen
• Reproduction.
Q35. Seasonal migration of fishes for breeding is called:
A. Photoperiodism
• Stimulus, not behavior.
B. Spawning migration ✅
• Anadromous/catadromous life cycles.
C. Schooling
• Group movement, not necessarily breeding.
D. Tagging
• Method of study.
Q36. Diadromous fishes include:
A. Only anadromous
• Subtype.
B. Only catadromous
• Subtype.
C. All fishes migrating between fresh & marine waters ✅
• Anadromous, catadromous, amphidromous.
D. Stenohaline only
• They are euryhaline.
Q37. The larval stage of many marine fishes is called:
A. Pupa
• In insects.
B. Fry (juvenile), or leptocephalus in eels ✅
• Hatchlings differ by group.
C. Caterpillar
• Not fish.
D. Maggot
• Not fish.
Q38. Otolith daily growth rings are useful for:
A. Determining sex
• Not rings.
B. Estimating age and growth rates ✅
• Increment analysis is fisheries tool.
C. Measuring buoyancy
• Swim bladder does.
D. Hormone levels
• Not true.
Q39. The FAO organization classifies world fish stocks mainly by:
A. Reproduction method
• No.
B. Overexploited, fully exploited, underexploited ✅
• To guide fisheries management.
C. Coloration
• Not relevant.
D. Length only
• Not sufficient.
Q40. Bycatch in fisheries refers to:
A. Target species
• No.
B. Non-target species accidentally captured ✅
• E.g., turtles, dolphins in trawls.
C. Juveniles of same species
• Still target.
D. Farmed fish
• Not bycatch.
Q41. Which gear causes most bycatch in marine fisheries?
A. Hooks & lines
• Relatively selective.
B. Trawls & gillnets ✅
• Capture many non-targets.
C. Traps
• More selective.
D. Cast nets
• Small-scale, low bycatch.
Q42. Aquaculture is defined as:
A. Catching wild fish
• That’s capture fishery.
B. Controlled farming of fish, mollusks, crustaceans, aquatic plants ✅
• Expanding food industry.
C. Preserving fossils
• Not aquaculture.
D. Fish marketing
• Not production.
Q43. India’s leading freshwater aquaculture fish is:
A. Tuna
• Marine.
B. Carps (e.g., catla, rohu, mrigal) ✅
• Backbone of Indian aquaculture.
C. Salmon
• Not native culture fish.
D. Tilapia
• Important, but carps dominate.
Q44. Integrated fish farming refers to:
A. Only fish rearing
• Not integrated.
B. Fish culture combined with agriculture/livestock (e.g., pig–fish, rice–fish) ✅
• Maximizes resource use.
C. Cage culture only
• Part of aquaculture.
D. Catch fishing
• Not aquaculture.
Q45. A major disease of freshwater fish caused by fungus:
A. Fin rot (bacterial)
• Not fungus.
B. Saprolegniasis (fungal cotton-like growth) ✅
• Affects eggs, fry, adults.
C. White spot
• Protozoan parasite.
D. Dropsy
• Bacterial.
Q46. Ciguatera fish poisoning is caused by:
A. Bacteria
• Not main.
B. Dinoflagellate toxins (ciguatoxins in reef fish) ✅
• Biomagnify in food web.
C. Virus
• Not.
D. Fungal toxins
• Not this.
Q47. Tetrodotoxin is found in:
A. Salmon
• No.
B. Pufferfish (fugu), some newts ✅
• Potent neurotoxin blocks Na⁺ channels.
C. Sharks
• No.
D. Tuna
• Not this toxin.
Q48. Fish oil is rich in:
A. Vitamin C
• Not abundant.
B. Omega-3 fatty acids (EPA, DHA) ✅
• Heart/brain health; important nutraceutical.
C. Calcium
• Mainly bones.
D. Carotenoids
• Pigment source but not main.
Q49. Which fish group has been most threatened by overfishing worldwide?
A. Catfish
• Cultured widely.
B. Large pelagic fishes (tuna, cod, sharks) ✅
• High-value, slow-reproducing species.
C. Tilapia
• Fast breeding.
D. Carps
• Widely farmed.
Q50. Marine Protected Areas (MPAs) are designed to:
A. Stop all fishing everywhere
• Not feasible.
B. Conserve habitats, allow recovery of fish stocks, protect biodiversity ✅
• Key fisheries management tool.
C. Export fish faster
• Not their role.
D. Train fishermen
• Separate programs.
Part 3 — Ichthyology MCQs (Q51–Q75)
Q51. The earliest jawless fishes belong to which group?
A. Chondrichthyes
• Cartilaginous, jawed fishes.
B. Osteichthyes
• Bony fishes.
C. Agnatha (lampreys, hagfish, ostracoderms) ✅
• Jawless vertebrates, oldest lineage.
D. Teleostei
• Modern bony fishes.
Q52. Hagfishes are unique because they:
A. Have jaws
• No, jawless.
B. Produce copious slime for defense ✅
• Slime clogs predator gills.
C. Have paired fins
• Absent.
D. Show metamorphosis
• Lampreys, not hagfish.
Q53. Lamprey larvae are called:
A. Fry
• Juvenile teleosts.
B. Ammocoetes ✅
• Burrowing, filter-feeding larvae.
C. Leptocephalus
• Eel larvae.
D. Tadpoles
• Amphibians.
Q54. Sharks differ from bony fishes by having:
A. Swim bladder
• Absent.
B. Cartilaginous skeleton and placoid scales ✅
• Chondrichthyes traits.
C. Operculum
• Absent.
D. Gills with covers
• Teleost trait.
Q55. The living “fossil fish” discovered in 1938 was:
A. Lungfish
• Survived too, but not “discovered” in 1938.
B. Coelacanth (Latimeria) ✅
• Lobe-finned fish, thought extinct since Cretaceous.
C. Gar
• Primitive ray-finned fish.
D. Hagfish
• Ancient, but known long ago.
Q56. Lungfishes survive droughts by:
A. Aestivation (burrowing + mucus cocoon, breathing air) ✅
• African lungfish famous for this.
B. Hibernation
• Seasonal cold dormancy.
C. Freezing
• Not strategy.
D. Salt secretion
• Osmoregulation in marine fishes.
Q57. Which organ allows many fishes to sense low light and depth?
A. Tympanum
• In amphibians.
B. Pineal organ + rod-rich retina ✅
• Adapted to dim environments.
C. Lateral line
• Detects vibration.
D. Ampullae
• Detect electricity.
Q58. Most freshwater fishes are:
A. Hypoosmotic to water
• That’s marine teleosts.
B. Hyperosmotic — body fluids more concentrated than surrounding water ✅
• Tend to gain water, lose salts.
C. Isosmotic always
• Sharks maintain near-isosmotic with urea.
D. Salt excreting
• Marine trait.
Q59. Antarctic icefishes (family Channichthyidae) lack:
A. Gills
• Present.
B. Hemoglobin (transparent blood) ✅
• Survive in O₂-rich cold water.
C. Swim bladder
• Some do lack it, but defining is Hb absence.
D. Vertebrae
• Present.
Q60. The rete mirabile in fishes is used for:
A. Gas exchange in gills
• Not main.
B. Countercurrent system to concentrate gases in swim bladder or heat in muscles ✅
• Tuna use for thermoregulation.
C. Digestive absorption
• Not rete’s function.
D. Egg development
• Not true.
Q61. The majority of fish diversity belongs to:
A. Agnatha
• Few extant species.
B. Chondrichthyes
• <1,500 species.
C. Teleostei (modern bony ray-finned fishes) ✅
• >30,000 species.
D. Sarcopterygii
• Very few.
Q62. Schooling in fishes benefits mainly by:
A. Oxygen uptake
• Not true.
B. Predator avoidance, foraging efficiency, hydrodynamic advantage ✅
• Classic ecological function.
C. Increasing reproduction only
• Secondary.
D. Disease prevention
• Actually increases risk.
Q63. Which fish uses electric discharge for communication and defense?
A. Catfish
• Vibrations mostly.
B. Electric eel (Electrophorus electricus) ✅
• Strong electric shocks, also signaling.
C. Tilapia
• Not electric.
D. Anchovy
• Schooling only.
Q64. Which gas primarily fills the swim bladder?
A. Nitrogen
• Not main.
B. Oxygen (secreted from blood via rete mirabile) ✅
• Provides buoyancy control.
C. Carbon dioxide
• Minimal.
D. Helium
• Not present.
Q65. Deep-sea anglerfishes exhibit:
A. External fertilization only
• No.
B. Extreme sexual dimorphism — tiny parasitic males fuse to females ✅
• Adaptation to low encounter rates.
C. No light organs
• They have bioluminescent lures.
D. Gills absent
• Present.
Q66. Which sensory system is essential for detecting water vibrations in murky rivers?
A. Retina
• Needs light.
B. Lateral line system ✅
• Neuromasts detect flow.
C. Olfactory rosettes
• Detect chemicals.
D. Electroreceptors
• Detect bioelectric fields.
Q67. Which structure in fishes is homologous to tetrapod lungs?
A. Gill arches
• Become jaws.
B. Swim bladder (in many ray-finned fishes) ✅
• Evolved from primitive lungs.
C. Operculum
• Protects gills only.
D. Scales
• Protective covering.
Q68. What adaptation allows desert pupfishes to survive extreme heat/salinity?
A. Hibernation
• Not strategy.
B. Extreme osmoregulatory plasticity (tolerate hypersaline & freshwater) ✅
• Euryhaline species.
C. Only hiding in mud
• Not main.
D. Producing uric acid
• Birds/reptiles.
Q69. The oldest living vertebrate known is:
A. Whale shark
• Large, but not oldest.
B. Greenland shark (Somniosus microcephalus) — lifespan >400 years ✅
• Longest-lived vertebrate.
C. Sturgeon
• Long-lived, but <200 years.
D. Lungfish
• Can live decades, not centuries.
Q70. Which fish can walk on land using fins?
A. Eel
• Can slither, not true walking.
B. Mudskipper (amphibious goby) ✅
• Modified pectoral fins for terrestrial mobility.
C. Tuna
• Open ocean swimmer.
D. Anchovy
• Pelagic.
Q71. Which fish has a spiral valve intestine like sharks?
A. Carp
• Simple intestine.
B. Dogfish shark (chondrichthyan) ✅
• Spiral valve increases surface area.
C. Tilapia
• Not spiral.
D. Eel
• Not spiral.
Q72. Which fish lacks a stomach?
A. Shark
• Has J-shaped stomach.
B. Many teleosts (e.g., carps) ✅
• Simple gut without stomach, rely on intestine.
C. Lungfish
• Have stomach.
D. Salmon
• Has stomach.
Q73. Which organ in fishes is analogous to mammalian kidneys for osmoregulation?
A. Swim bladder
• Buoyancy, not excretion.
B. Kidneys (head kidney & trunk kidney in fishes) ✅
• Regulate ions and nitrogen excretion.
C. Lateral line
• Sensory.
D. Operculum
• Not excretory.
Q74. Which fish shows parental care by building bubble nests?
A. Salmon
• No nests.
B. Betta (Siamese fighting fish) & gouramis ✅
• Male guards bubble nest.
C. Cod
• Broadcast spawners.
D. Tuna
• No nest.
Q75. In food webs, fishes act as:
A. Primary producers
• Plants/algae do.
B. Consumers (primary, secondary, tertiary) ✅
• Roles vary: herbivores, planktivores, piscivores.
C. Decomposers
• Not fishes.
D. Detritivores only
• Only some species.
Part 4 — Ichthyology MCQs (Q76–Q100)
Q76. The largest fish in the world is:
A. Blue whale
• Mammal, not fish.
B. Whale shark (Rhincodon typus) ✅
• Filter-feeding shark, up to 18 m long.
C. Giant grouper
• Large, but smaller.
D. Oarfish
• Very long, but slimmer.
Q77. The fastest fish in the ocean is:
A. Tuna
• Fast, ~75 km/h.
B. Sailfish (Istiophorus platypterus) ~110 km/h ✅
• Uses sail-like dorsal fin & slender body.
C. Shark
• Great white slower.
D. Barracuda
• Fast but less.
Q78. Which fish is called the “living fossil” among ray-finned fishes?
A. Cod
• Modern teleost.
B. Gar & bowfin ✅
• Primitive actinopterygians with ganoid scales.
C. Catfish
• Modern group.
D. Tilapia
• Domesticated.
Q79. The largest freshwater fish is:
A. Salmon
• Smaller.
B. Beluga sturgeon (up to 1,500 kg) ✅
• Source of caviar.
C. Catla
• Aquaculture species, smaller.
D. Trout
• Smaller.
Q80. Which fish is most widely cultured globally?
A. Tuna
• Not farmed widely.
B. Carps (esp. common carp, rohu, catla) ✅
• Dominant in Asia.
C. Salmon
• Important in North America/Europe.
D. Tilapia
• Rising but second to carps.
Q81. In India, the “Indian major carps” include:
A. Tuna, salmon, mackerel
• Marine, not Indian.
B. Catla, rohu, mrigal ✅
• Main freshwater aquaculture fishes.
C. Trout, perch, catfish
• Not Indian major carps.
D. Sardine, anchovy
• Marine.
Q82. Tilapia is often called:
A. “Indian carp”
• Incorrect.
B. “Aquatic chicken” due to fast breeding and growth ✅
• Important aquaculture fish.
C. “Milk fish”
• Refers to Chanos chanos.
D. “Silver fish”
• Not tilapia.
Q83. Which marine fish is famous for ciguatera poisoning in humans?
A. Salmon
• Safe to eat.
B. Reef fishes (grouper, barracuda, snapper) ✅
• Accumulate dinoflagellate toxins.
C. Tuna
• Causes scombroid poisoning, not ciguatera.
D. Cod
• Not ciguatera.
Q84. Which fish is invasive in Indian waters?
A. Catla
• Native.
B. Common carp and tilapia ✅
• Introduced, impact native biodiversity.
C. Rohu
• Native.
D. Mrigal
• Native.
Q85. The “Hilsa” (Tenualosa ilisha) is:
A. Catfish
• Not Hilsa.
B. Anadromous clupeid (sea → river for spawning) ✅
• National fish of Bangladesh.
C. Eel
• Catadromous.
D. Salmon
• Not Hilsa.
Q86. “Tor” species (mahseer) are important because:
A. Marine fish
• No, freshwater.
B. Sport fish and threatened freshwater resource in Himalayas ✅
• Conservation priority.
C. Only aquarium fish
• Not true.
D. Salt-tolerant
• Not typical.
Q87. Which fish is famous for biofluorescence and biomedical imaging research?
A. Tuna
• Not used.
B. Zebrafish (Danio rerio) ✅
• Model organism in genetics, development, toxicology.
C. Goldfish
• Not main model.
D. Shark
• Some biomedical use, but not main.
Q88. Zebrafish is an excellent model organism because:
A. Long generation time
• Opposite, they are short.
B. Transparent embryos, rapid development, easy genetics ✅
• Makes them ideal for labs.
C. Expensive to rear
• They are cheap.
D. Only marine
• Freshwater.
Q89. Which fish produces antifreeze proteins to survive freezing seas?
A. Tuna
• Not adapted.
B. Antarctic notothenioids ✅
• Special glycoproteins prevent ice crystal growth.
C. Catfish
• Not this adaptation.
D. Tilapia
• Tropical.
Q90. Which fish is used as a bioindicator of water pollution?
A. Goldfish
• Popular pet.
B. Common carp, tilapia, minnows ✅
• Sensitive to heavy metals, pesticides.
C. Shark
• Not used in freshwater.
D. Grouper
• Not indicator species.
Q91. Which fish produces isinglass, used historically for clarifying beer/wine?
A. Salmon
• Not source.
B. Sturgeons (swim bladder collagen) ✅
• Valuable gelatin-like substance.
C. Tuna
• Not isinglass.
D. Carp
• Not main source.
Q92. Which family includes tuna and mackerels?
A. Cyprinidae
• Carps, minnows.
B. Scombridae ✅
• High-speed pelagic fishes.
C. Cichlidae
• Perches.
D. Clupeidae
• Herrings, sardines.
Q93. Which family includes herrings, sardines, anchovies?
A. Scombridae
• Tuna, mackerel.
B. Clupeidae ✅
• Key small pelagic fishes.
C. Siluridae
• Catfish.
D. Salmonidae
• Salmon, trout.
Q94. Which fish is used to produce surimi (fish paste)?
A. Hilsa
• Too oily.
B. Pollock & other whitefishes ✅
• Used for imitation crab sticks.
C. Shark
• Used in fin soup, not surimi.
D. Tuna
• Not for surimi.
Q95. Which invasive fish is called the “Frankenfish” in USA?
A. Goldfish
• Harmless invasive.
B. Snakehead fish (Channa spp.) ✅
• Aggressive, air-breathing predator.
C. Tilapia
• Invasive but less threatening.
D. Carp
• Invasive but not Frankenfish.
Q96. Which fish is considered sacred in many Indian temples?
A. Shark
• Not sacred.
B. Mahseer, catla, carp species ✅
• Protected in temple ponds.
C. Tuna
• Marine, not temple.
D. Salmon
• Not in India.
Q97. Which adaptation allows lungfish to breathe air?
A. Swim bladder
• Modified into lungs.
B. True lungs connected to pharynx ✅
• Evolved from primitive sarcopterygian lungs.
C. Operculum
• Gills, not lungs.
D. Kidneys
• Osmoregulation, not air-breathing.
Q98. Which fish is the largest bony fish in the world?
A. Whale shark
• Cartilaginous.
B. Ocean sunfish (Mola mola) ✅
• Up to 2 tons, flattened body.
C. Grouper
• Large, smaller than sunfish.
D. Cod
• Much smaller.
Q99. The major threat to global fish biodiversity is:
A. Predation
• Natural.
B. Overfishing, habitat destruction, climate change, invasive species ✅
• Multiple combined pressures.
C. Evolutionary changes only
• Too slow.
D. Salinity
• Local stress, not global.
Q100. Why are fishes crucial to human nutrition?
A. Only luxury food
• Not true.
B. Major source of animal protein, omega-3s, micronutrients for billions ✅
• ~20% of global animal protein intake.
C. Only for fertilizers
• Secondary use.
D. Only for aquaria
• Not main reason.
ichthyology mcqs for cbse board exams, ichthyology objective questions for icse students, ichthyology mcqs for neet preparation, ichthyology practice questions for cuet ug pg, ichthyology mcqs for csir net life sciences, ichthyology questions for gate biotechnology exam, ichthyology mcqs with explanations for dbt bet jrf, ichthyology mcqs for usmle step 1 preparation, ichthyology practice questions for plab exam, ichthyology mcqs for amc medical licensing, ichthyology multiple choice questions for sat biology subject test, ichthyology practice test gre biology subject exam, ichthyology mcqs for bmat entrance preparation, ichthyology objective questions for imat exam practice
