20. Zebrafish 2 - Husbandry, Management, Techniques, Euthanasia

What largely regulates internal body temperature in a poikilotherm?

environmental temperature

Why is methyl blue added to the embryonated eggs?

suppresses fungal growth

Since ZF are poikilotherms this means that water temperaturechsnges should be limited to +/- ____ per day

1.5C a day

ZF are also eurythermal meaning they can have an acclimated thermal tolerance of ____ to ____

44-107F

Optimal temperature for ZF growth and breeding?

24-28C

What is the standard embryonic temperature?

28.5 C (~83F)

What is the TNZ for ZF per the guide?

75-82F

What is the recommended room temperature and humidity level in zebrafish room?

28.5C (83.3F); 70%

Metabolic rates in ZF double for every ____C increase in temp

10C

If the water is too cold more ___ offspring will be born

male

The ambient room temperature should ____ compared to water temperature

1-2 degrees higher

To prevent condensation of water on aquaria, room air should be around _____

24-27C

Ambient room temp over ___ is not recommmended due to cost of maintaining high temp and higher metabolic rate of fish

27C

How often should water temperature be checked per the guide?

daily

A decrease in the water temperature causes what pros and cons?

-increased oxygen availability (warmer = lower dissolved oxygen), reduces need of food, minimizes loss due to accidental temp increases

-decreases rate of growth and development

How does a fish asphyxiate outside of water?

gill lamellae clump together, decreases surface area available for oxygen diffusion

Picture that indicates oxygen depletion in tank

large number of fish gathered at point of air supply

If you see a large number of fish gasping or sipping at water's edge or gathered around an air stone, top of tank, or near airators, this indicates what?

oxygen depletion within system

What causes gas bubble dz?

super saturation of water with oxygen or nitrogen gas

How does super saturation of water with oxygen or nitrogen usually occur?

-cavitating water pumps

-air stones placed too close to water pump inflow

When is compressed air normally added to the water system?

filtration zone

How often should recirculating water be turned over?

once an hour

Oxygen diffusion from room air is adequate for depths less than _____

4 inches

When should dissolved oxygen be moitored more intensely?

-when fed intensively

-held at densities >15 fish/L

Compressed air is often hot and dry, what does this do to the water in the system?

causes it to evaporate quicker

Air bubbling creates a mist which does 2 things we don't want

-fomite/pathogen transfer

-corrode metal

What is the ideal water pH for ZF?

7-8 pH

pH >8 results in what?

increased concentration of toxic unionized ammonia (NH3)

pH <5 inhibits what?

nitrifying bacteria which causes an increase in ammonia due to accumulation

In a closed and recirculating system the pH will gradually ____ due to production of ____ from what process?

-decrease

-acids

-nitrification process (ammonia converted to nitrate)

in poorly aerated systems, CO2 production will lead to ____pH

decreased

Metallic contaminants like ___, ___, ____, and ____ are more water soluble in acidic water

zinc, copper, iron, aluminum

____ is the indicator of the total amount of dissolved ions in a solution

conductivity

Conductivity is also a direct measure of the ____ that an aqueous solution can conduct. It us an imprecise measurement of ____.

-electric current

-salinity

Why should conductivity be monitored in a system?

evaporation changes salinity

ZF will tolerate salinities between ____ and ____

125-2500uS (microseimens)

Larvae can be successfully reared in salinities up to for ___ 5-10dpf, but not advised to do so

5g/L

_____ is the amount of calcium and magnesium salts in the water

total water hardness

Calcium is measured as ___ in total water hardness

calcium carbonate

ZF are a softwater or hardwater species?

Hardwater (80-200 ppm of calcium and magnesium)

How can softwater be detrimental to fry?

increased susceptibility to disease, reduces embryo survival

___ and ___ water removes some or all minerals. What can be used to replace lost minerals?

-reverse osmosis or distilled water

-CaCO3, crushed coral, aragonite prep

In the nitrification cycle name the order of most to least toxic.

Ammonia (NH3), Nitrite (NO2), nitrate (NO3)

What leads to the formation of ammonia (NH3)?

-uneaten/decaying food

-nitrogenous waste excretions

How is ammonia (NH3) converted to nitrite (NO2)?

-AOB and AOA (ammonia oxidizing bacteria and ammonia ozidizine archaea)

-Nitrosomonas spp. & nitrospira spp. & nitrosococcus spp.

-aeromonas and pseudomonas

How is nitrite (NO2) converted to nitrate (NO3)?

-NOB (nitrite oxidizing bacteria)

-nitrospira spp and nitrobacter spp.

-aeromonas and pseudomonas

Why is the biofilter important?

harbors the bacteria that are important to the nitrification cycle

The biofilter is living. This means that ___ will alter the biofilter. ____ will dislodge bacteria and _____ can "crash" it

-anitbiotics

-mechanical disruption

-abrupt change in aquatic environment

Water changes (not too frequent and not too large a volume) are important to prevent build up of

____ which can overload and kill the biofilter

nitrate

Ammonia and nitrite are both toxic, but nitrate is only toxic close to ____.

200mg/L

What are the 4 filtration methods?

-mechanical

-chemical

-biological

-UV

The mechanical filter removes what? how does it accomplish this?

-solid wastes

-porous filter, filter pads/sponges, granular media

The chemical filter removes what? How does it do this?

-dissolved wastes, heavy metals, organic compounds

-granular activated carbon

The biological filter removes what? How does it do this?

-nitrogenous wastes

-biomedia with surface which nitrifying bacteria can grow

The UV filter does what? How does it do this?

-microorganism disinfection

-UV-C

What is the germicidal action spectrum of UV light?

240-280nm

FACILITIES Section

How many % of overall tank should be used as storage and preparation tanks?

10% of overall tank census be dedicated for storage and preparation

Types of floors and walls for ZF housing room

water resistant - epoxy coated

Threshold in ZF housing room should be ____ meaning there should be a raised seperation between room and hallways

bermed

What type of drainage system is best?

multiple drains rather than 1 drain w/ steep flooring

What kind of silicone sealer should be used with ZF tanks?

food grade silicone

What material of pipping should be avoided? What should be used instead?

-Copper and lead

-aluminum or stainless instead

When do you need to treat the outgoing water for ZF?

when its not going to a sanitary sewer line

What is the recommended light cycle in zebrafish room?

14:10

What is the recommended lighting in zebrafish room?

300 lux at 1 meter height

What is the recommended lighting in ZF room per the BBB?

5-30ft candles or 54-354 lux at water level surface

How many air changes in ZF room?

enough to keep humidity levels normal

An outdoor HVAC intake and compressed air intake should be filtered when?

-in agricultureal area (pesticides and herbicides)

Electrical outlets should be ___ or in water proof conduits ____ from floor. Outlets should also be ___

-suspended

-4ft from floor

-ground fault interrupted

Should ZF rooms have emergency power?

yes (aeration, filtration, lighting)

Avoid treated wood instead use

heavy duty plastic or stainless steel

Which color LED light is detrimental to zebrafish?

Red colored LED

Which society defines the water quality

ASTM (American Society for Testing and Materials)

What are the 4 types of caging systems for ZF?

-static

-flow through

-recirculating

-modular

In a static system what filtration is used?

none

What should be provided in a static system?

-air pump/stone

-heater to maintain temperature

When is a heater not necessary in static caging?

overnight breeder tanks

What is static housing good for?

-short term housing

-quarantine, emergency hospital/tx, test tanks, breeding

What percent water change should be done daily for static tanks?

75% minimum

How does water flow in a flow through system

-enters source, flows through filtration, into tanks, exits via overflow pipes

What is normally present in a flow through system?

-mechanical and chemical filtration

-temperature regulating ability

-carbon filter to remove chlorine

Flow through system are great for what animals?

-amphibians

-not ZF

How much water should be changed daily in recirculating system?

10%

How is old water released in flow through system?

overflow pi8pes

The ____ is where all the filters are maintained in a recirculating system

sump

Know the basic parts of a ZF tanks

What are the benefits to a modular system?

-completely self contained - closed reciculation

-easy access to popes, mechnical components. contains independent life support system

-allows for expansion of facility if necessary

-most practical and economical

What is the best plastic to use for ZF caging?

polycarbonate (acrylic warps)

It's best to get plastic that is _____ as it can lead to reproductive problems in alot of animals, fish included

BPA free or bisphenol A

Nets should be disinfected between tanks, how do you do that?

-2% bleach (sodium hypochlorite)

-1% virkon (potassium peroxymonoslfate + sodium chloride)

_____ will dissolve undissolved protein in water

foam fractioner

Why is it a terrible idea to use freshwater snails (Planorbella spp) for algae removal?

-reproduce quickly (can block pipes)

-vector for larval stags of parasites (digenetic trematodes)

-reservoir for bacterial pathogens (Mycobacterium spp.)

How should algae levels be controlled in ZF caging unit?

-decrease light levels

-decrease frequency and amount of feed

What is the best water source for ZF? Why?

-Deep wells

-few infectious agents, toxic chemicals, may contain heavy metals

If using municipal water source, must remove what?

chlorine, copper, cholramines

Which water processing method removes ALL minerals? Which one removes most?

-all - distilled

-most - RO/deionized

What water evaporation ___ increases

salinity

How to remove chloramines and chlorine?

-chemical - sodium thiosulfate

-reverse osmosis

-carbon filtration

-aeration for 24hr (chlorine only)

How often should chlorine be monitored? What should it be at?

-daily

-0ppm