Fish Dissection
For the Dissection
Step 1: External structure
- Identify the key features of this fish. Postulate what purpose they might serve to assist the fish to function underwater.
Step 2: Gill Flap Removal
- Carefully cut around and remove the gill flap to expose the gills
- Separate the gills
Step 3: Identify Gill structures
- Once you have done this you may wish to run the gills under some water to see what they are like underwater. could you notice any changes in the structure of the gills?
Step 4: Mouth/ Teeth investigation
- From the mouth, can you identify what kind of food this fish eats? Is it a herbivore or a carnivore? Why?
Step 5: Cut into the abdomen
- Begin from up near the mouth and slice back towards the tail. Be careful not to perforate the intestines or internal organs.
- Identify what you can see inside the fish
- Are these organs similar to human organs? How do they differ
Step 6: Identify the Heart
- this heart is a 2 chambered heart.
Step 7: Identify the liver if possible and stomach
- Gently slice open the stomach. Is it empty?
Step 8: Identify the intestine.
- What is this called instead of an intestine?
Step 9: Identify the swim bladder
- This is deeper in the fish behind the organs. You may need to move the organs to find the swim bladder
- What is the purpose of the swim bladder?
Step 10: Identify the Gonads
- Can you tell if this fish is male or female? Why?
Vocabulary: Parts of the fish
• Anal Fin - fin located near the anal opening; used for balance and steering.
• Caudal or Tail Fin - fin at the tail of a fish; used for propulsion.
• Circulatory System - delivers blood and oxygen throughout the body via the heart.
• Digestive System – breaks down and processes proteins, carbohydrates and fats.
• Dorsal Fin – backside (top) fin on a fish; used for balance and protection.
• External Anatomy - the outside body parts, such as, fins, scales, mouth.
• Gills – organ used to obtain oxygen from the water and rid carbon dioxide.
• Gill Rakers – filter feed tiny prey; appendages along the front edge of the gill arch.
• Gonads – the sex organs; males have testes, females have ovaries. Some fish are hermaphroditic, meaning having both sets of gonads (male & female) in one fish.
• Lateral Line – organ of microscopic pores that sense low vibrations and water pressure.
• Nares - organ to smell; similar to nostrils.
• Nervous System - organs receiving and interpreting stimuli for nares, eyes, lateral line, muscles, and other tissues.
• Pectoral Fin - fins on the sides; used for balance and assist turning.
• Pelvic Fin - belly fins on a fish; used for balance and steering.
• Pyloric Caece – “finger-like” organ that aids in digestion, using bile from the liver.
• Reproductive System – the organs and tissues involved in reproduction, including gonads, eggs, sperm.
• Respiratory System – organs and tissues involved in the oxygen & carbon dioxide gas exchange, including gills, gill rakers, and gill filaments.
• Scales - protective cover on a fish; similar to skin.
• Slime – slippery covering on scales, protecting fish from bacteria, parasites, etc.
• Swim bladder – found only in “ray-finned” fish; a double sac used to assist in buoyancy.
• Urinary System – the kidneys remove nitrogen (ammonia) from the blood and regulate water balance in the blood and tissues.
• Vertebrate – an organism with a backbone or spine
• Anal Fin - fin located near the anal opening; used for balance and steering.
• Caudal or Tail Fin - fin at the tail of a fish; used for propulsion.
• Circulatory System - delivers blood and oxygen throughout the body via the heart.
• Digestive System – breaks down and processes proteins, carbohydrates and fats.
• Dorsal Fin – backside (top) fin on a fish; used for balance and protection.
• External Anatomy - the outside body parts, such as, fins, scales, mouth.
• Gills – organ used to obtain oxygen from the water and rid carbon dioxide.
• Gill Rakers – filter feed tiny prey; appendages along the front edge of the gill arch.
• Gonads – the sex organs; males have testes, females have ovaries. Some fish are hermaphroditic, meaning having both sets of gonads (male & female) in one fish.
• Lateral Line – organ of microscopic pores that sense low vibrations and water pressure.
• Nares - organ to smell; similar to nostrils.
• Nervous System - organs receiving and interpreting stimuli for nares, eyes, lateral line, muscles, and other tissues.
• Pectoral Fin - fins on the sides; used for balance and assist turning.
• Pelvic Fin - belly fins on a fish; used for balance and steering.
• Pyloric Caece – “finger-like” organ that aids in digestion, using bile from the liver.
• Reproductive System – the organs and tissues involved in reproduction, including gonads, eggs, sperm.
• Respiratory System – organs and tissues involved in the oxygen & carbon dioxide gas exchange, including gills, gill rakers, and gill filaments.
• Scales - protective cover on a fish; similar to skin.
• Slime – slippery covering on scales, protecting fish from bacteria, parasites, etc.
• Swim bladder – found only in “ray-finned” fish; a double sac used to assist in buoyancy.
• Urinary System – the kidneys remove nitrogen (ammonia) from the blood and regulate water balance in the blood and tissues.
• Vertebrate – an organism with a backbone or spine