FAQs Zebrafish Related Frequently Asked Questions

General Zebrafish Facility Questions

1How do I increase Zebrafish laboratory and facility efficiency and streamline operations for my team and staff?

Some ways to increase productivity within your zebrafish rooms is to have well-written standard operating procedures (SOPs) within your room, so that all team members (new and old) can easily refer back to them or learn the ins and outs of your procedures and protocols more efficiently.

A big-time, energy, and headache saver: Lab Animal Colony Management Software (South Boston Life Science Corp).

Also, investing in innovative, practical solutions for your lab such as fish feeders, environmental monitoring control panels, dosing systems, etc. will all help streamline, standardize, and automate everyday mundane, sometimes tedious processes. Although these products (sometimes) will cost more than the cheaper alternative options, we find our customers find our suggestions well worth it long-term (from a time, energy, and financial perspective).

For other ways to optimize your zebrafish operations, please reach out to us: hello@daniolab.com

2What kind of record-keeping should be implemented in a zebrafish lab?

Some variables to document include: daily/weekly water quality parameters and environmental conditions (temperature, pH, conductivity, nitrate, nitrite, ammonia, etc.), feed-outs, staff time in/time out, relevant life support maintenance, work to be done, work completed, etc.

3How do you prolong and extend the life of your zebrafish facility and research?
One way to do this is to purchase quality products and invest in preventative maintenance programs and service care plans. At Danio Lab, we are experienced in providing high-quality, long-term care plans to our clients so they can get the most out of their systems. Contact us for more info: hello@daniolab.com
4I need help building, constructing, designing my zebrafish facility, where do I go?
At Danio Lab, we are experienced and knowledgeable in all aspects of Zebrafish husbandry, operations, and system design/installation, health monitoring, and more. With over 20+ years of experience in the field as a total, full-service zebrafish husbandry company, we can help you complete your projects.
5How do you ship and transport zebrafish?
Fish should ideally be double bagged with the density being around 10 fish/0.5 gal (2/3 of the bag should be oxygen). It’s wise to not feed your fish before shipping, as you don’t want them to excrete inside the bag (in static water) causing a less than ideal environment for them during transit


1How many types of zebrafish housing systems are there?
Generally speaking, there are three types – centralized system, distributed system, and a stand-alone system. All three can be used for different purposes based on your specific lab’s current and future goals. It’s common that labs have a large centralized, flow-through system and then a couple of stand-alone systems for experiments or quarantine.
2What should be the light cycle/photoperiod for my zebrafish room?
It’s recommended that you have 14 hours light and10 hours dark. The best way to do this is to install a timer in your fish room so it is consistent every day. This can affect health and breeding performance.
3How do I acclimate new incoming fish to my system?
One way to acclimate them is to float the bags they come in within your system water to allow the temperature to equilibrate for about 15 min. Once complete, you can scoop the fish out of the bag using a net (disregarding the water within the bags) and place them into a quarantine rack. Allow fish to recuperate for up to a couple of weeks before breeding.

Water Quality

1What are the standard water quality parameters (for zebrafish)?
  • Temperature: ~ 27 degrees Celsius
  • pH: ~ 7.0 - 8.0
  • Conductivity: ~ 500-1000 uS
  • Ammonia: 0 ppm, Nitrite: 0 ppm, Nitrate 0-5 ppm
  • Exchange rate: ~ 10% every day
2How to maintain your zebrafish filtration system components
  • Biomechanical clarifier: automatically backwashes daily, clean out sludge once a week
  • Filter pads: Change 2x week
  • Conductivity (probe): clean + calibrate every 2 weeks
  • pH (probe): clean + calibrate every 2 weeks
  • UV Sterilizer: lamp – replace yearly, quartz sleeve – replace every 2 years, 0-rings – replace every 2 years
  • RO Filter (carbon): replace every 2 months
  • RO Filter (sediment): replace every 2 months
  • RO (membrane): replace every 2 years
  • RO (water maker): flush once a week
3How to monitor and test your water quality parameters?
There are a few ways to monitor and test water quality – one being strip tests, where you can dip strips into system water and then match to the appropriate colors. There’s also more advanced digital YSI meters you can utilize to give you more precise readings. We found that using a water analyzer like the LaMotte WaterLink Spintouch FF is an easy, efficient, and precise way to analyze your water.
4My nitrate levels are high, what should I do?
The system might be overdue for a water change. Also make sure you are not overfeeding or overcrowding your system, this can lead to degraded water quality especially if your system isn’t quite capable of handling it.
5My pH levels are too high, what should I do?
To lower your pH, triturating acid will solve the issue or utilizing an acid solution via your dosing system. Another way to decrease your pH is to add CO2 to your system.
6My pH levels are too low, what should I do?
One way to do this is to add sodium bicarb to your system.
7My ammonia levels are high, what should I do?
It’s possible there are too many fish in your system, so you might have to decrease your densities to a more sustainable level. It could also be due to low pH levels, which could mean your bacteria have stopped nitrifying bacteria. In addition, especially if it’s a new system, it could also mean your bacteria colonies haven’t fully established themselves yet and you might have rushed the initial cycling process when starting a new system.
8How many zebrafish can I keep in my tanks, how many fish per liter?

Depending on your system, filtration capabilities, etc., you should keep around 5-15 fish per liter. Adult fish, that is.

For larval zebrafish, it’s suggested you can keep around 40 fish per liter.

9When do you transfer larval fish from the nursery to the main/central housing and filtration system?
Typically, once your nursery fish are done being fed rotifers (or complete their polyculture stage) or their initial larval diet, and are being fed a more standardized diet diet (such as a dry formulated feed and Artemia), they can be transferred to the main system. Usually, anywhere from the 14-21 dpf range.
10Water supply - Can I use tap water in my zebrafish facility?

The water you use for your RAS is dependent on your local water supply. Depending on the quality of your incoming water, you might not have to make major adjustments to it. Chlorine, Hardness, and other impurities will dictate your methodology.

If your zebrafish filtration system has a RO or DI line (reverse osmosis or deionized) then you probably don’t have to pre-filter your water, however if you’re using say city water, you will need to utilize a carbon filter.

Water filtration can be tricky – contact us today for step-by-step assistance: hello@daniolab.com

11What is quarantine and is it necessary?
When new fish arrive, it’s important to keep them isolated from the rest of your colony to prevent any potential harmful diseases and pathogens from transmitting to them. A quarantine period is usually anywhere from 2-4 weeks in a separate system (from your main central flow-through racks). If new embryos arrive to your lab, they should also be acclimated and then sanitized with a very mild bleach solution.

Filtration System

1My filtration system was down and shut down for a while, should I be worried about my biological filtration unit?
If the system was only down for 24 hours or less, the important nitrifying bacteria in your filter will probably be fine – however if your system was off for 2-3 days or more, the bacteria in your system will probably have to be re-established. To restart the nitrifying bacteria, there are a few ways to do this – one method being, obtain some biological media from another active/existing biological filtration unit and place it into the filter unit that was off and has to be restarted. The introduced bacteria will begin to re-establish and re-colonize over the next couple of days.
2How to clean your sump?
Turn off all system components. Use a siphon to clean any organic matter/debris that might exist. Turn back on all pumps and system components.
3My system pumps are on – why isn’t there any water flow?
The pump impeller might be clogged or not working properly.

Monitoring System & Control Panels


1Why aren’t my zebrafish breeding?
There are a variety of factors that influence breeding performance including: water quality, diet/nutrition, feeding regimes, photoperiod, temperature, age of fish, male/female ratio, housing, spawning setup, etc. Narrowing down these variables and factors is the first step at addressing what the potential problem could be (such as stocking density or malnutrition). Stressed fish will not spawn, so your breeding performance can also be looked at as a proxy for how good your husbandry conditions are.


1What’s the best nutrition/feed for zebrafish?
There’s not really any optimal standardized diet for zebrafish out there but generally it’s best to introduce live prey items to zebrafish early on and then gradually wean them onto a formulated dry diet (increasing the food particle size as they get larger). Typically, from 5 dpf-11dpf, larvae will go into a polyculture system using a green-water technique. Adults should get fed a nutritious dry feed twice a day.
2What is polyculture?
Polyculture is a common and effective early feeding methodology involving the use of microalgae, rotifers, and larval zebrafish (usually 5 dpf - 11 dpf). The zebrafish are cultured together with rotifers in a static system, where microalgae is added to provide food for the rotifers, and the rotifers serve as live prey for the zebrafish.

Fish Diseases/Pathogens

1What are some of the common zebrafish-related diseases to be aware of?
Pseudoloma neurophilia (microsporidiosis), fish tuberculosis (mycobacteria), velvet disease.


1How do you prevent algae growth on your tanks?
This might mean your nitrate levels are too high. Make sure you are not overfeeding as that is a common culprit. Do up to 10% water changes every week to keep nitrate levels in check. Ensure your UV sterilizers are effectively working. Ensure your nitrifying bacteria populations are doing their job. Check light fixture orientation and bulb type.
2How do you clean your fish tanks?
If you do not have a cage wash system, it’s recommended to thoroughly clean tanks using a sponge/brush with hot water. The use of detergent isn’t necessary (as it can be potentially harmful to fish), unless the tanks are severely dirty, then a very mild bleach solution could be sparingly used. You can also use thiosulfate to neutralize any possible leftover bleach after as well.

Environmental Enrichment

1Should I add enrichment to my zebrafish tanks?
Although physical enrichment has become necessary for rodents, there are still no studies that clearly show any benefit/improvement in the welfare and health of zebrafish in regards to having sources of enrichment within their tanks. Single housed zebrafish may or may not benefit from say a plastic plant, however the chance of toxic chemical leaching from plastic additives is now introduced.

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