Washington University in St. Louis School of Medicine

Zebrafish Facilities

WUSTL-SOP-001:   Zebrafish Husbandry

Zebrafish (Danio rerio) Husbandry Guidelines


This document will provide general guidelines for Zebrafish care in the Washington University School of Medicine Basement Facility.


Larval Husbandry:


Disclaimer: All times of development will be based on the standard 28.5C rearing temperature, variations from this temperature will result in accelerated or retarded development and will require commensurate adjustments to the rearing schedule of larval zebrafish.


0-4 days post-fertilization (dpf): larval zebrafish require no external food sources as they are surviving on their yolk and lack a complete G.I. tract. These larvae are typically kept in Petri dishes or aquaria in static water.


Beginning at 5-6 dpf: larval zebrafish will be transferred from their hatching containers (i.e. Petri Dishes) and fed live rotifers enriched with a microalgae one to two times per day. The algae will consist of nannochloropsis, tetrasalmis or green algae of similar cell size and nutritional value. In the event that rotifers are unavailable, a suitable prepared larval diet will be provided. Larvae will be housed in densities ranging from <1 to approximately 10 larvae per liter, with a range of 8-10/L being ideal. Examples: a 1.1L tank may house up to 15 larvae, a 3.5L tank may house up to 40,  and an 8.0L tank may house up to 80 fish.


Laval zebrafish will be provided with size-appropriate diet. For example, rotifers may be fed in combination with algae until the larvae are big enough to eat artemia nauplii, at which time rotifers will be discontinued and artemia nauplii and a prepared diet will be fed.  As the fish progress in their growth and development, larger food items will be provided, until they are moved to the adult fish holding areas. If live foods are not available for first-feeding larvae, dry diets may be used but water flow in the form a a drip is required to prevent fouling of the tank.



Adult Fish Husbandry:


Adult fish are moved from the Nursery to the Adult Fish Holding rooms at ~50-days, or when they have reached a size adequate to prevent them from swimming through the opening of the adult tank baffle (approx. 20mm), and are housed at a density of <1-12 fish/L.


Adult fish held on the recirculating system are fed a minimum of once per day, and may be fed three or more times per day, using a prepared dry food and or artemia nauplii.




Anesthesia is accomplished using tricaine methane sulfonate (a.k.a. Mesab, MS-222, Tricaine, Finquel) using a stock solution of 4g/L buffered to pH 7.4 by Trizma Base.


Euthanasia is accomplished using an overdose of tricaine or rapid cooling (see WUSTL SOP-005 Zebrafish Euthanasia)


Life Support System Parameters:


Water chemistry will be maintained as follows:


Zebrafish Water Quality Parameters

The system shall maintain the water quality within the following parameters:




Water Temperature

24°C - 30°C

26.5°C - 29°C

Room Temperature

24°C - 29°C


Total Gas Pressure

<20 mmHg or 70-102%

<20 mmHg or <100%

Water Exchange

1-10 % / Day

1% / Day





650-4000 µS

850-2000 µS

Ammonia (NH3)

< 0.25 ppm

0.0 ppm

Nitrite (NO2)

0-25 ppm

0 ppm

Nitrate (NO3)

0-80 ppm

10 ppm


0.3-3 ppt


Flow Rate

3-6 Tank Vol./Hour


UV Disinfection

15-32 mW sec/cm2

20-30 mW sec/cm2







Larval zebrafish are fed live diets, such as rotifers or paramecia, and prepared diets such as Argent Hatchfry Encapsulon grade 0 or I, or Ziegler AP-100 grade 1.


Juvenile zebrafish are fed live artemia nauplii as well as prepared diets such as Argent Hatchfry Encapsulon grade 0 or I, or Ziegler AP-100 grade 1, and a blend of commercial quality aquaculture foods such as Lansy NRD 4/6, Salt Creek Progression 4, and Argent Cylop-eze.


Adult zebrafish are fed a blend of commercial quality aquaculture foods such as Lansy NRD 4/6, Salt Creek Progression 4, and Argent Cylop-eze, as well as live artemia nauplii.











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