U5Ch30 : Fish

Question 1

common uses of fish in research

Answer 1

A variety of fish species are used in biomedical research to study endocrinology, bacterial diseases, and the genetics of human development and metabolism. Toxicity studies are also frequently conducted using fish. Research is also being conducted on the nutrition, health, and husbandry of fish due to the increasing importance of aquaculture, the raising of fish as a source of food. In addition, fish are studied in their natural habitats, and may be utilized as bioindicators, to provide a measure of the health status of the environment and ecosystem.

Question 2

most commonly used fish in research

Answer 2

zebrafish

Question 3

nomenclature/ taxonomy of fish used in research

Answer 3

Zebrafish (Danio rerio) : family Cyprinidae (+ carp and minnows) genus Oncorhynchus : trout and salmon

Question 4

What is the scientific name for the zebrafish?

Answer 4

Danio rerio

Question 5

What is the operculum?

Answer 5

a bony, flexible plate that covers and protects their delicate gills

Question 6

What is the lateral line?

Answer 6

Fish have a sense organ called the lateral line that runs along each side of their body and allows them to detect movements and vibrations in the water.

Question 7

What is the gas bladder?

Answer 7

(also called the air or swim bladder) which helps the fish maintain buoyancy and control its position in the water.

Question 8

What fish organ extracts oxygen from the water?

Answer 8

gills

Question 9

Oviparous

Answer 9

they lay eggs and rely on external fertilization

Question 10

Spawning

Answer 10

The release of eggs and sperm

Question 11

general sexual dimorphism seen in fish

Answer 11

In general, females of live-bearing species are larger than the males, although the male is more brightly colored. Female egg layers often have a swollen abdomen when ready to spawn

Question 12

General breeding protocol for zebrafish

Answer 12

Breeding zebrafish may be accomplished with many males and females in a single large tank, or with only one or two males and females in a very small breeding tank. Breeding tanks usually have a perforated insert through which eggs fall to the tank bottom. This protects the eggs from being eaten by the adults. Usually fish are put together in the tank late in the day and spawning occurs the next morning. The eggs are collected and the fish are returned to their respective housing tanks. Fish used for egg collection use more energy than the regular stock fish, and must be fed adequately to compensate for the extra energy used in egg production. Fish should not be used for egg collection more than once a week

Question 13

What is the correct water temperature for raising zebrafish?

Answer 13

28.5 C

Question 14

Which statement about breeding zebrafish is FALSE?
Fish used for breeding should be fed more food than nonbreeding fish.
One or two pairs can be placed in a small breeding tank.
Fish are placed in the same tank in the morning, and eggs are usually collected at the end of the day.
Breeding tanks are used to separate the eggs from the adults.

Answer 14

Fish are placed in the same tank in the morning, and eggs are usually collected at the end of the day.

Question 15

When plastic bags containing fish are received into the facility, what should be the first step to acclimate the fish?

Answer 15

Float the bag in the receiving tank until the bag reaches the same temperature as the water in the tank.

Question 16

Which statement is TRUE regarding fish quarantine?
It is a good procedure to share equipment and tools between the quarantine system and the established fish system.
Quarantined fish should be moved to the established fish population after a minimum of two weeks.
Work in the quarantine tanks should be done at the beginning of the day.
In some institutions, the fish in quarantine are used only to produce embryos.

Answer 16

In some institutions, the fish in quarantine are used only to produce embryos.

Question 17

common behavior observed in fish

Answer 17

Fish are normally inquisitive and most are quite active. Noticeable behavior changes are often associated with reproduction or feeding. Some fish aggressively defend territories; crowding often causes greater aggressiveness as well as stress or injury to other fish. Fighting occurs among some species, and can be reduced by separating aggressive individuals.

Question 18

Which anesthetic agent is commonly used with fish?

Answer 18

MS-222

Question 19

Which statement is FALSE?
Fish will become more docile with repeated handling.
General anesthesia can be used when handling fish.
Wet gloves should be worn when handling fish.
Each tank or group of similar tanks should have their own set of restraint equipment.

Answer 19

Fish will become more docile with repeated handling.

Question 20

Identification used with fish

Answer 20

In animal facilities, fish may not have to be individually identified; records can be kept per tank. However, some studies require that fish be individually identified. Common methods of individual identification include subcutaneous dye injections (the less invasive method), visible implant elastomer (VIE) tags, fin clipping, and subcutaneous or abdominal transponders. In some cases, a record of individual body patterns serves to identify the fish. The method used depends on the type of fish and the specific research being conducted. Tags should be inserted under anesthesia; their size, shape, and placement should allow for normal behavior, and not cause the fish to get entangled within its habitat.

Question 21

What identification method is NOT commonly used in fish?

Answer 21

Tattoo

Question 22

behaviors associated with stress and disease in fish

Answer 22

changes in feeding (such as refusing or spitting out feed)
erratic movements like flashing (scraping against objects in the tank)
isolation from the school
lethargy
gulping air at the surface of the tank (piping)
swimming in circles or disorientation

Question 23

Changes in appearance noted in fish when ill

Answer 23

abnormally lightened or darkened skin
erosion of skin, fins or gills
clamped fins
loss of buoyancy control
rapid movement of or flaring of the operculum

Question 24

What is a behavioral change that may indicate pain or distress in zebrafish?

Answer 24

Piping
Flashing
Lethargy

Question 25

What would NOT be a physical sign of pain or distress in a fish? Inquisitiveness loss of buoyancy control Change in skin color Opercular flaring

Answer 25

Inquisitiveness

Question 26

Fish should not be used for egg collection more than once per: month. year. day. week.

Answer 26

week