center for research animal resources workshop fish health management paul r. bowser aquatic animal...

Center for Research Animal Resources Workshop

Fish Health Management

Paul R. BowserAquatic Animal Health Program

Department of Microbiology and ImmunologyCollege of Veterinary Medicine

Cornell UniversityIthaca, New York 14853-6401

[email protected]

mailto:[email protected]

Workshop Overview

• Water Quality Management – General Comments

• Important Water Quality Parameters

• Monitoring Water Quality

• Aquarium Systems

• Aquaculture Systems

• Fish Physiology Basics

Workshop Overview (cont.)

• Disease Diagnosis – how you can help us better help you

• Your “Fish Room”

Water Quality Management –General Comments

• Water as a “Universal Solvent”

Will dissolve a lot of substances

Oxygen

Toxins


• Specific gravityChanges with water temperatureIn general: as T ↑ Specific Gravity ↓Maximum at 4CImportance: uniformity(you don’t want water with different

specific gravity in your fish holding system)

This is mostly a problem in a large (i.e. pond) system


• HardnessAmount of divalent cationsPrimarily Ca++ and Mg ++

Hardness can have interactions with

other water quality parameters and disease treatment compounds

Want hardness at approximately

100 mg/L (as equivalent CaCO3)


• Alkalinity

Carbonate, Bicarbonate and Silicate

Important in providing buffering capability

Capability to resist a change in pH

Stability of pH is desirable


• pH

Log of the inverse of the hydrogen ion concentration

Log function

Freshwater: pH = 7.0 – 7.2

Saltwater: pH = 7.8 – 8.0

Ideal (in general) stay near the normals


• Specific heat

The amount of energy it takes to change the temperature of a given

substance

Water has a high specific heat

It takes a lot of energy to change the temperature of a given volume of water

Water temperature can be changed slowly

Important Water Quality Parameters

THE WATER SOURCE IS OF PARAMOUNT IMPORTANCE

Well water

Spring water – devoid of living organisms, especially potential vectors of fish pathogens

Surface water – wild fish are a source of pathogens

filterUV treatOzone treat


Water Temperature

The ideal for the species

An acceptable range for the species

Tropical fish

Cool water fish

Cold water fish


• Dissolved Oxygen

As water temperature ↑, O2 carrying capacity ↓Temperature O2 at 100% Saturation (mg/L)

5 12.76

10 11.28

15 10.07

20 9.08

25 8.24

30 7.54



As water temperature ↑, O2 carrying capacity ↓

Temperature O2 at 100% Saturation (mg/L)

5 12.76

10 11.28

15 10.07

20 9.08

25 8.24

30 7.54NOTE: A fish at 25C deals with 8.25 ppm DO; we deal with 20 per cent (parts per hundred)


• Dissolved Oxygen– Note: As Temperature ↑ DO at 100% Saturation ↓

• BUT: As T ↑, O2 requirement of FISH ↑• Problem: Not enough O2 at higher water

temperature to support the needs of the FISH


• Nitrogenous compounds

Ammonia (NH3/NH4+)

↓ Nitrosomonas

Nitrite (NO2)

↓ Nitrobacter

Nitrate (NO3)


• Nitrogenous compoundsAmmonia ↓ Nitrosomonas Nitrite (NO2) ↓ Nitrobacter

Nitrate (NO3)

The reaction is aerobicThe biological filter must not become

anaerobic


• Nitrogenous compoundsAmmonia (NH3 + H+ NH4

+)

High pH High T

Nitrite

Nitrate

NH3 (unionized ammonia) is the toxic form

A greater % of total ammonia is in the unionized form at higher pH and temperature

pH has the greater impact

Important Water Quality Parameters - Ammonia

Temperature (C)______________________________________________________________pH 10 12 14 16 18 20 22 24______________________________________________________________ % of Total Ammonia in Unionized Form 7.0 0.18 0.22 0.25 0.29 0.34 0.39 0.46 0.52

8.0 1.82 2.12 2.47 2.86 3.30 3.81 4.38 5.029.0 15.65 17.82 20.18 22.73 25.46 28.36 31.40 34.56

10.0 64.98 68.44 71.66 74.63 77.35 79.83 82.07 84.08______________________________________________________________

pH had a dramatic impact on % of total ammonia that is in the unionized form

i.e. W = 30” L = 12” W X L = 360 in2

30”

30”12”

12”

FW Tropical: (L X W)/12 = 30 (“inches” of fish)

FW Coldwater: (L X W)/30 = 12

SW Tropical: (L X W)/48 = 7.5

A SW Tropical tank can only hold ¼ the fish biomass as a similar FW Tropical tank.

Carrying Capacity 12”

12”

30”

30”

12”

12”

A SW Tropical tank can only hold ¼ the fish biomass as a similar FW Tropical tank.

WHY THE DIFFERENCE?

AMMONIA and pH

Saltwater is buffered at 7.8 – 8.0

Freshwater is buffered at 7.0 – 7.2

Almost 10X the ammonia will be in the toxic unionized form

Carrying Capacity

12”

12”


• Chlorine

Chlorine can be highly toxic to fish

Found in municipal water

Need to remove:

Sodium thiosulfate

Allow Chlorine to dissipate with time

Aeration/agitation will speed release


• Other potential toxicantsWide variety of compounds

pesticidesfertilizerspollutants (may have BOD)gasessmokeetc………….

Monitoring Water Quality

Common sense

This is not a “one size fits all situation”

You should evaluate your system and develop a rational schedule for water quality monitoring.


• Water Temperature– Goal to maintain at the optimum for the species

unless the protocol specifies otherwise– Rapid water temperature change is a stressor

A rapid 5C water temperature change suppressed the immune system of channel catfish for 4-6 weeks.

Monitor daily unless you expect frequent temperature changes


• Dissolved Oxygen– Ponds will have a diurnal DO pattern

6am 6pm 6am

Diurnal nature of DO is due to photosynthesis and intensity of sunlight

Need to monitor DO at daily “low point” (early morning)


• Dissolved Oxygen– Raceways with gravity flow

• Agitation and aeration provides DO

– Tanks• Air pumps• Air blowers• If you have a choice, don’t use compressors

• Dissolved Oxygen should not be a problem in raceways and tanks due to movement of water and/or mechanical devices.


• Total Ammonia and pH

Ammonia (NH3 + H+ NH4+)

High pH

High TNew Tank Syndrome (first 30 days)

Conc.

Time (days) 30 days

NO2 NO3NH3/NH4+


• Nitrite– Ammonia → Nitrite → Nitrate– Toxic (conc. as low as 0.5 mg/L)– Brown Blood Disease, Methemoglobinemia– Nitrite oxidized hemoglobin (brown color)– The oxidized hemoglobin can’t carry

oxygen– Signs of respiratory distress


• Hardness and Alkalinity– Interactions with Tx compounds

– CuSO4 and alkalinity• Copper sulfate toxicity increases as

Alkalinity decreases

Aquarium Systems


1. Air stones

2. Air/water interface

3. Utilizers of oxygen

4. Producers of oxygen

Aquaria: mechanical

Ponds: photosynthesis

Water Circulation

Oxygen

Aquaculture Systems

• Temperature– Optimum for fish– Interactions between temperature and DO

• Metabolism increases• Oxygen requirement increases• Food intake increases

– Temperature as a Stressor• Elevated Temperature• Temperature Change

Opt.

Lethal

OK

High

Low

Aquaculture Systems

Filtration:

Biological

Mechanical

Chemical

Undergravel Filter: biological, mechanical filter

Outside Power Filter: mechanical, chemical, biological filter

Aquaculture Systems

• Filtration– The need for filtration – Required for a closed

system– Types of Filtration

• Mechanical – remove particulate matter• Biological – performed by bacteria

Nitrosomonas, Nitrobacter – detoxify N-compounds

Capability/Capacity: a function of surface area of the filter medium

• Chemical – remove small molecular weight compoundsDisease Tx compounds

Aquaculture Systems

• Filtration– Types of filters

• Mechanical: foam, filter floss, gravel (1/4-1/8” dia.)• Biological: create a large surface area to be colonized

by the Nitrosomonas and Nitrobacter– foam, floss, gravel

• Chemical:

activated carbon dolomite

zeolite ion exchangers

peat moss

Aquaculture Systems

• Filtration – Corner Filter

Filter Floss

Activated Carbon

Aquaculture Systems

• Filtration: Outside Power Filter

Sponge, water conditioners or zeolite can also be added

Activated carbon

Filter floss

To electric

AQUARIUM

Aquaculture Systems

• Filtration – Undergravel Filter

Aeration through water movement

Power Head

Air lift pump

Aquaculture Systems

• Filtration – foam filter

Movement of water can be through the use of an air lift pump or a power head

Foam filter has limited capability– hospital tank; fry tank

Aquaculture Systems

• Filtration – Canister Filterssuch filters are usually on very large systems

External Internal

Activated Carbon

Filter Floss

Aquaculture Systems

• Water ExchangesDilutes waste products, corrects pH

pH

Organics

Nitrite

Nitrate

Ammonia

Water Change

TIME

Water Quality Management

• Raceways: water flow = carrying capacity• Ponds: pond depth and photosynthesis

dissolved oxygen

ability of pond to conduct nitrogen cycle to detoxify N-compounds

• Cages: total carrying capacity = that of the body of water had the cages not been present

Water Quality Management(cont.)

• Recirculation Systems:

Water must be managed/monitored carefully

DO: provided mechanically

Detoxification of N-compounds:

performed by large biofilters

Need to carefully monitor the performance of these life support systems

center for research animal resources workshop fish health management paul r. bowser aquatic animal...

Documents

water source

higher water temperature

given substance water

system slide

temperature ph

normals slide

desirable slide

anaerobic slide