Aquaculture Technician Certification
Exam – 100 Questions
1. Which water quality parameter is most critical for fish respiration?
A. pH
B. Dissolved oxygen
C. Alkalinity
D. Hardness
Rationale: Fish rely on dissolved oxygen for respiration; low levels
quickly cause stress or death.
2. A common sign of ammonia toxicity in fish is:
A. Darkened coloration
B. Gasping at the surface
C. Increased grazing behavior
D. Schooling more tightly
Rationale: Ammonia damages gills, reducing oxygen uptake, causing
fish to surface for air.
3. The primary purpose of a biofilter in a recirculating system is to:
A. Remove solids
B. Oxygenate water
C. Convert toxic nitrogen compounds
D. Add minerals
Rationale: Biofilters support nitrifying bacteria that convert ammonia
and nitrite to less harmful nitrate.
4. What is the optimal pH range for most freshwater aquaculture
species?
,A. 4.5–5.5
B. 5.0–6.0
C. 6.5–8.5
D. 8.5–9.5
Rationale: Most cultured species thrive between pH 6.5 and 8.5,
minimizing stress and toxicity.
5. Which species is most commonly grown in cage culture?
A. Salmon
B. Tilapia
C. Catfish
D. Both salmon and tilapia
Rationale: Both salmon (cold-water) and tilapia (warm-water) are
widely farmed in cage systems.
6. The nitrogenous waste most toxic to fish is:
A. Nitrate
B. Nitrite
C. Ammonia (NH₃)
D. Ammonium (NH₄⁺)
Rationale: Unionized ammonia (NH₃) is highly toxic even at low
concentrations.
7. The main function of aerators is to:
A. Remove solids
B. Reduce pH
C. Increase alkalinity
D. Increase oxygen levels
Rationale: Aerators increase water–air interface, optimizing oxygen
transfer into water.
8. Which fish disease is caused by a parasitic protozoan?
, A. Columnaris
B. Ich (Ichthyophthirius multifiliis)
C. Streptococcus
D. Aeromonas
Rationale: Ich is a protozoan parasite causing white spot lesions.
9. A sign of poor feed quality is:
A. High protein level
B. Rancid smell
C. Uniform pellet size
D. Slow sinking rate
Rationale: Oxidized fats give feed a rancid odor and can harm fish
health.
10. Which method is commonly used to transport live fish?
A. Clay pots
B. Plastic-lined trucks
C. Open buckets
D. Oxygenated plastic bags or tanks
Rationale: Oxygenated bags/tanks maintain water quality and
oxygen during transport.
(Continuing…)
11. The term “FCR” refers to:
A. Fish Consumption Rate
B. Feed Conversion Ratio
C. Feed Chemical Reaction
D. Fish Condition Rating
Rationale: FCR measures feed efficiency—feed input vs. biomass gain.
Exam – 100 Questions
1. Which water quality parameter is most critical for fish respiration?
A. pH
B. Dissolved oxygen
C. Alkalinity
D. Hardness
Rationale: Fish rely on dissolved oxygen for respiration; low levels
quickly cause stress or death.
2. A common sign of ammonia toxicity in fish is:
A. Darkened coloration
B. Gasping at the surface
C. Increased grazing behavior
D. Schooling more tightly
Rationale: Ammonia damages gills, reducing oxygen uptake, causing
fish to surface for air.
3. The primary purpose of a biofilter in a recirculating system is to:
A. Remove solids
B. Oxygenate water
C. Convert toxic nitrogen compounds
D. Add minerals
Rationale: Biofilters support nitrifying bacteria that convert ammonia
and nitrite to less harmful nitrate.
4. What is the optimal pH range for most freshwater aquaculture
species?
,A. 4.5–5.5
B. 5.0–6.0
C. 6.5–8.5
D. 8.5–9.5
Rationale: Most cultured species thrive between pH 6.5 and 8.5,
minimizing stress and toxicity.
5. Which species is most commonly grown in cage culture?
A. Salmon
B. Tilapia
C. Catfish
D. Both salmon and tilapia
Rationale: Both salmon (cold-water) and tilapia (warm-water) are
widely farmed in cage systems.
6. The nitrogenous waste most toxic to fish is:
A. Nitrate
B. Nitrite
C. Ammonia (NH₃)
D. Ammonium (NH₄⁺)
Rationale: Unionized ammonia (NH₃) is highly toxic even at low
concentrations.
7. The main function of aerators is to:
A. Remove solids
B. Reduce pH
C. Increase alkalinity
D. Increase oxygen levels
Rationale: Aerators increase water–air interface, optimizing oxygen
transfer into water.
8. Which fish disease is caused by a parasitic protozoan?
, A. Columnaris
B. Ich (Ichthyophthirius multifiliis)
C. Streptococcus
D. Aeromonas
Rationale: Ich is a protozoan parasite causing white spot lesions.
9. A sign of poor feed quality is:
A. High protein level
B. Rancid smell
C. Uniform pellet size
D. Slow sinking rate
Rationale: Oxidized fats give feed a rancid odor and can harm fish
health.
10. Which method is commonly used to transport live fish?
A. Clay pots
B. Plastic-lined trucks
C. Open buckets
D. Oxygenated plastic bags or tanks
Rationale: Oxygenated bags/tanks maintain water quality and
oxygen during transport.
(Continuing…)
11. The term “FCR” refers to:
A. Fish Consumption Rate
B. Feed Conversion Ratio
C. Feed Chemical Reaction
D. Fish Condition Rating
Rationale: FCR measures feed efficiency—feed input vs. biomass gain.
