Inside the Tank: A Peek into the Tecniplast Annual International Zebrafish Husbandry Course, 2023 Part III/III

Admin ZHA • September 1, 2024

by Charli Corcoran

The Lectures: top tips and takeaways

The course was rather intense, we had a jam-packed schedule from the course’s start on
Monday evening. It began with an opportunity for networking and to introduce ourselves to
each other and a keynote speech addressing all the amazing things that zebrafish can be
used for in research.  It was a chance for us all to consider what we use zebrafish for in our
own facilities and to potentially think outside the box for ways that we could use the fish in
the future. The rest of the week was a mix of talks and social events that gave us a good
balance of learning and networking. I thought that the topics covered through the week were
a good range, covering the broader aspects of zebrafish care while also focusing on more
specific topics of interest.  

I struggled to choose which lectures to summarise as there were 27 talks throughout the
week, plus a round table event at the end, each talk addressing a different aspect of zebrafish management. I have chosen 7 that I felt were relevant to the wider community.

 Disease and Disease Management
 Health Monitoring
 Water Quality Fundamentals
 “Refinement” and “Setting and Validating Standards”
 Genetic Colony Management
 Enrichment
 Sustainability

“Not only were they presented in an easy to listen to style but the vast knowledge of information given has allowed me to develop our facilities protocols and improve them to benefit us.”

-Paul Strachan, University of Edinburgh

Disease and Disease Management. 
There were several presentations about disease and the management
of disease, given by Lauren and Justin.  The two speakers did a really
great job of addressing the types of infectious and chronic diseases
that we should look out for in our facilities, and importantly, how to manage them, from both
a husbandry perspective and a facility management perspective. This talk series was one of
the most important for me, and probably for a lot of people as the pathogens are present in
our facilities.

Some top tips from Lauren and Justin’s talks were: 

 Understanding the design of our facility and whether it is doing its job properly helps
to mitigate the risk of disease
 Check the efficiency of your UV filter, don’t just assume that it is working properly.
Monitor the flow rate and the UV dose.
 Check your mechanical filters: what is actually getting through?
 Consider work flow and how that can help manage existing pathogen burden
 Colony health management planning is key to controlling your existing pathogenic
burden
 Use an online reporting system that notifies the users about any issues with their fish,
using health indicators and body condition scoring charts.

“Personally, listening to topics on disease control, genetic colony management and disaster planning I found extremely useful!”
-Paul Strachan, University of Edinburgh

Health Monitoring
Bruce and Justin discussed health monitoring.  They encouraged us to take the time every
day to observe everything we can about the fish, and to make sure that all staff are trained to
recognise an unhealthy fish.  They talked about the different types of sampling for
diagnostics purposes, and what we should sample: fish, water, biofilms – and encouraged us
to think about what detection, or even lack of detection, of pathogens or microorganisms
might mean.
Key takeaways about Health Monitoring:

 Have a quarantine facility away from the main work room and consider your workflow
 Make decisions beforehand so that it is easier to decide in the moment, and have a
plan for what you will do if your monitoring gets a positive result
 Use sick fish charts and record what you are seeing so you can monitor trends.
Review logs regularly.
 Remove sick fish at earliest opportunity
 Investigate mortalities that shouldn’t have occurred
 Fecundity monitoring can be an early indicator for any problems.

Water Quality Fundamentals
This was one of the presentations that I was looking forward to going into the course, as
some areas of water quality continue to be a challenge for our facility. I was keen to hear
what Karen had to say on the topic and to discuss our concerns with other zebrafish people. 
Karen’s talk addressed the impact of water parameters on zebrafish welfare. Water
parameters have a complex relationship with each other and it was good to relate some of
those with some potential welfare issues that we might see in our fish.
Some of Karen’s Water Quality dos and don’ts:

 Zebrafish can tolerate a wide range of environmental conditions but they do not
tolerate sharp changes so acclimate your fish to any changes slowly 
 Remove chlorine using carbon filters

Water Hardness
 Low alkalinity can increase the toxicity of dissolved metals
 The recommended range for zebrafish is 50-75ppm
 Soft water (<60ppm) results in difficulties maintaining egg supply or survival

pH
 Haemoglobins affinity for oxygen decreases as pH decreases
 Nitrogenous waste is more toxic at high pH levels
 Zebrafish can tolerate a wide range 

Temperature
 Higher temperatures speed up development and aging and also food
consumption
 Activity and behaviour are highly affected by temperature
 Toxicity of nitrogenous waste increases with temperature
 Dissolved oxygen decreases as temperature increases
 Chlorine and Chloramines
 Low levels of chlorine cause stress and irritated gills
 High levels are fatal

Water Flow
 High water flow is good for adult fish, high occupancy tanks, tanks in rooms
with low ambient temperatures and tanks getting a lot of food. 
 Low water flow good for younger fish and for blind fish

Static Tanks
  Check water quality of static tanks regularly
 Change water regularly

Refinement and Setting and Validating standards.
Carrie’s talk on refinement in zebrafish, and Lauren’s talk on setting and validating
standards, were very motivating, encouraging us to make the small changes and
refinements that can be implemented at a local level, to do the validation studies, to publish
the results, and apply it from a facility management perspective.  

“I agree that there should be more publications on zebrafish husbandry and
welfare for zebrafish enthusiasts to learn and grow together as a community.”

-Iris Y.K. Woo, University of Hong Kong.

Key messages from the refinement and setting and validating standards presentations:

 We can be so focused on trying to make big changes, that we overlook the small
improvements that we can make at a local level in our own facilities.
 Small changes can lead to improvements in welfare
 Start by asking the question “Why do you do it that way?”

 Validate your changes and publish any results: Zebrafish Journal* would be a good
place to start with publishing any results.
 Always assess the ‘new thing’ that you heard at the conference with what works in
your facility and with your users

*I did not know about the Zebrafish journal, here is a link for anyone like me:
https://www.liebertpub.com/loi/zeb.  

Genetic Colony Management of Zebrafish 


“Working in a breeding area, it was inspiring to understand different ways of
genetic colony management and principles behind. I can share those knowledges
with the researchers for the team having healthier and sustainable colonies”

-Iris Y.K. Woo, University of Hong Kong.

This session was of interest to many of the attendees, and Karin focused on things to
consider in preventing and identifying phenomena such as inbreeding depression and the
founder effect in our zebrafish colonies.  She also linked good genetic health with the 3Rs:
how developing methods that focus on high survival is a good way to minimise the number
of animals used (Reduce), and she discussed methods to maintain good genetic diversity in
our wildtype stocks.

Some of the key messages from Karin’s talk on genetic colony management are:

 Inbreeding depression can be a slow process and you may not always see it happening.  It leads to reduced biological fitness in the population. It’s easier to address and prevent in mutant, transgenic and knockout lines with outcrosses and incrosses, but it typically occurs in wildtypes and is harder to address
 To mitigate, set a minimum survivor threshold and if survival drops below a certain percentage, do not use the line.
 Try to determine the cause of each event.
 Find your baseline and track deviations
 3 to 1 rule: for every 3 crosses, you should outcross to wildtype and rederive. Include cross number on tank labelling so it’s easy to keep track of.

Wildtype maintenance strategies:
 Use a minimum of 25 crosses
 Screen clutches for size, quality and fertility
 Keep clutches separate for the first couple of days and eliminate those that
didn’t meet the screening criteria.  If there are 25 clutches, use them for the
next generation. If not, start again.  (25 can be scaled down depending on
your intended numbers).
 Quality Assessment: screen every day
using a scoring rubric.
 Reduce direct sibling matings: after screening, create individual tanks with
non-related fish OR mix females and
males so they aren’t siblings
 Regular importation of new fish stock to
introduce genetic material

Enrichment 
Enrichment is another topic that we are discussing a lot in our facility at the moment, and a
topic which some of our undergraduate students are in the process of looking into, so I was
really interested in this session, and to hear the speakers and attendees’ views on
enrichment in zebrafish facilities. Karin defined enrichment as additions or modifications to
the basic laboratory environment which aim to improve laboratory animal welfare. She talked
about the benefits and objections, and the different types of enrichment that we might
encounter in our facilities.
Top Enrichment tips: 

 Enrichment is not one size fits all: consider age, group size and sex
 Habituation can lead to lack of interest, so change enrichment frequently
 Simple tank changes can improve welfare
 Communicate changes with staff and users

Sustainability in a Fish Facility
I was looking forward to this session as sustainability is a topic that’s heavily discussed in
the wider environment of our institute.  I think it can be quite overwhelming to think about
how we can be more sustainable in a facility where the large majority of our equipment has
to be running all the time.  This session was a little different to the rest of the week, as we
divided up into small groups and separated out to discuss the ways which we have been
able to be more sustainable in our own facilities, and share ideas to help others take steps to
be more sustainable.  

Obviously not all the ideas and solutions will be viable in all facilities, but having that time to
discuss in a group and hear how things had worked out in different facilities around the world
was very useful.


Some of those ideas: 
 Adjust feeding regime to reduce required cleaning and filter changes and to reduce
food waste.
 Look at ways we can reduce our consumable use: wash the filter mats in hot water
instead of replacing them every time, and clean petri dishes in a bleach solution.  In
this particular case, washing the petri dishes had cut down on petri dish purchase by
90%.  Biodegradable petri dishes were also suggested, as was the use of glass petri
dishes.
 Adjusting water exchange when the total system volume changes to make sure that
water is not being wasted.
 Recycling the water that we use.

I really enjoyed the format of this session and I do wish there had been other opportunities to
discuss specific topics in more formal settings like this throughout the course.


“Some of the things discussed on the course we already know, but was not
enforcing. Now we also know of the consequence it can have, which have made us
enforce it and are making sure the researchers know why as well.”

– Michael Henningsen, University of Copenhagen

I fully agree with Michaels point that a lot of the things that were discussed on the course
were things that many of us already knew, but didn’t really have any ways of enforcing in our
facilities or with our users.  The course empowers us to enforce those things by sharing
some of the consequences of not enforcing those steps.

Each presentation had time for discussion afterwards. These were sometimes lively
opportunities to ask specific questions which had come up during the course and it was
really great to hear all the questions that the attendees had. 


“I gained a lot of insights and useful information through sharing my challenges.”
-Iris Y.K. Woo, University of Hong Kong


Like Iris, I found these discussion times helpful, as well as the more informal networking at
lunch or during the social time.  I found it helpful to be able to hear about issues that other
facilities had encountered, as there is always the potential for those problems to crop up for
me in the future. There was also the opportunity to write down any questions or topics for
discussion, and put them in the fish tank. A round table was held at the end of the week,
where the panel of speakers answered or discussed the questions that had been left in the
tank. This was a fantastic opportunity to get expert opinions on any zebrafish related topics.

Zebrafish at the 16th FELASA Congress in Athens, Greece

By Joana Monteiro • December 31, 2025
The 16th FELASA congress took place last June 2-5, 2025 in Athens. The congress offered a dynamic mix of scientific sessions, technical workshops, and informal exchanges. It brought together a great diversity of professionals - researchers, facility managers, technicians, veterinarians, officials of the regulatory bodies, vendors - all committed to advancing laboratory animal science in line with the 3Rs. The congress also fostered a strong sense of community. Whether it was over coffee or during the evening socials, there was time for valuable conversations about everything from tank design to ethics committee reviews. And the ZHA was beautifully represented by members of the Executive Board and volunteers!! While the programme covered a wide range of species and models, zebrafish had a stronger presence than ever. Regulatory topics drew strong attendance and included the reporting of experimental animals and genetically modified fish. There were extensive discussions on the 2024 updates to EU Directive 2010/63/EU. The primary focus was on strategies for meeting the new minimum requirement of 1 liter of accessible water per zebrafish. Most commercially available breeding tanks currently do not comply with this regulation. In the absence of ready-made solutions, one interesting approach presented was a custom-made insert designed to fit 3.5L holding tanks already in use at the facility. This insert provides over 1L of swimming space while separating adults from spawned eggs. It also promotes sustainability by repurposing existing tanks rather than requiring new purchases. A workshop on severity assessment in fish offered real case studies and helped attendees refine welfare scoring and end-point assessment for zebrafish and other aquatic species. Methods for anesthesia and euthanasia were revisited. One presentation introduced a fully optimized setup for euthanizing zebrafish directly in their standard housing tanks using electrical stunning. Although this method represents a significant refinement in fish euthanasia, its broader adoption may be limited by the lack of commercial availability. Facilities would need to invest in custom-building the setup, which may pose a challenge in terms of cost and technical resources. In another presentation, the audience was reminded of chemical methods other than MS222, including lidocaine hydrochloride 1 g/L, buffered with 2 g/L of sodium bicarbonate and mixed with 50 mL/L of ethanol, which seems to be a faster and less aversive method of euthanasia for both adults and larvae. Secondary methods for confirmation of death were also discussed. Welfare refinement was another hot topic. It was great to see an increasing number of evidence-based enrichment protocols, with new evidence in favour of physical environmental enrichment. The data showed the impact of visual barriers, substrate mimics, and tank complexity on fish behavior and physiology. Other topics discussed included refinements of genotyping methods and health monitoring, risk assessment, and control of pathogens transmission, among others. Several sessions offered practical suggestions for zebrafish management and care, including facility design, husbandry best practices, early disease detection, and larval rearing techniques. Beyond the formal sessions, the poster area also counted with zebrafish content. As we continue to refine husbandry and welfare practices, and navigate evolving regulations, gatherings like the FELASA congress are essential for sharing knowledge and building a knowledgeable, collaborative, and forward-thinking community. And last but certainly not least, a heartfelt thank you to the Zebrafish Husbandry Association, who awarded me one of the 2024 Advancement Grants. Your support helped make my attendance to this congress possible!

Presenting ‘The 3Rs in Zebrafish Research’ at The European Zebrafish Husbandry Association meeting in Gödöllő, Hungary

By Kamar Ameen-Ali • December 31, 2025
In October 2024, I travelled to Gödöllő in Hungary for the second European Zebrafish Husbandry Association meeting (EZHAM); the first having taken place in London two years earlier. I had been invited to give a talk opening the 3Rs session, as the meeting coincided with the recently published book ‘Zebrafish: A Practical Guide to Husbandry, Welfare, and Research Methodology’, edited by Dr Claire Allen and Dr J-P Mocho. In this book, I had authored a chapter entitled ‘The 3Rs in Zebrafish Research’ and it was this topic I would be giving my talk on. I’m a neuroscientist and dementia researcher, with a strong interest in bioethics, specifically the ethical use of animals in scientific research. I’m a senior lecturer at Teesside University in the UK, but I previously worked for the NC3Rs, a UK-based organisation that funds research and leads initiatives to promote and implement the 3Rs in scientific research. For those who may not be aware, the 3Rs (Replacement, Reduction, Refinement) are an important ethical and legislative framework for the use of animals in scientific research. In research where zebrafish are used as a model organism, replacement may involve using mathematical or computer modelling as a complete replacement of the use of zebrafish, or alternatively using embryonic or foetal forms of zebrafish as partial replacement. Reduction refers to using the most appropriate number of zebrafish required to obtain statistically meaningful results and using methods and techniques to minimise the use of zebrafish where possible. Finally, refinements in zebrafish research involve any method or approach which can improve welfare or reduce potential harm to zebrafish. In my role with the NC3Rs, I worked with researchers and animal facility staff across several universities to share best practice, as well as being a member of several ethics committees where I advised on the 3Rs in animal-based projects. Presenting at EZHAM provided me with an opportunity to inform delegates about advancing the 3Rs in zebrafish research, and share current research on zebrafish welfare, including husbandry methods and techniques. Gödöllő is situated about 20 miles northeast from Budapest, the capital city of Hungary. To keep financial costs down, I decided to stay in a hotel I’d been in before on a previous trip to Budapest and get the short train ride to and from Gödöllő on the days of the meeting. The station in Gödöllő was located at the bottom of a small hill, with the venue a short walk to the top. I always feel that the best way to get a sense of a new place is by using public transport, and I thoroughly enjoyed travelling on the local trains with the commuters. The meeting was hosted at the Institute of Aquaculture and Environmental Safety of the Hungarian University of Agriculture and Life Sciences. The specific venue was the Agricultural Machinery and Technology Curiosity Museum, which housed many fascinating exhibitions on historical use of machinery and equipment, which we could explore during the breaks. When I arrived, I registered and took a wander around the exhibitors which were interspersed among the museum items. The posters were in a separate room adjacent to the large seminar room where the talks would be held. The meeting was extremely well organised, and it was clear that a lot of thought had gone into the best way to host a hybrid meeting and deliver a positive experience for online delegates. Professional cameras and recording equipment were set up, with around four or five dedicated technical staff responsible for this side of things. This meant I could give them my presentation slides without worrying about any IT issues, which is always the most stressful part of giving a talk! Having the meeting recorded also meant myself and other delegates could go back and watch any talks we enjoyed or may have missed. Before I discuss my 3Rs talk, I want to share some of my personal highlights from the meeting. Of the posters, there were two that particularly appealed to my interests. The first was by Lisa Van Hateren from the University of Sheffield, UK. The poster evaluated methods of genotyping zebrafish and how procedure numbers can be reduced by genotyping embryos or using methods which are more refined than the commonly used fin clipping of zebrafish adults. Secondly, Anita Rácz from the University of Glasgow, UK, presented some interesting data on refining commonly used visible implant elastomer identification tags, with potential welfare benefits. There were some fantastic talks throughout the meeting, including two by Professor Lynne Sneddon from the University of Gothenburg, Sweden. I’ve seen Professor Sneddon give talks on a number of occasions and it’s always a pleasure to hear her present her research which has truly advanced zebrafish welfare, and our understanding of this species as it has gained popularity as a model organism. Professor Sneddon shared her work on environmental enrichment, as well as methods to assess zebrafish welfare, recognising pain, and pain management protocols. A talk by Dr Christian Lawrence from SmartLabs, USA, generated interesting discussions on a topic which is applicable across many areas of laboratory science, not just zebrafish research. Protocols and environmental conditions can vary greatly across labs and institutions, but should we be striving for greater standardisation? Human diseases and conditions can have significant variation in how they present, which can be attributable to heterogenous genetic and environmental factors. Perhaps greater translation between animal and human studies can be achieved by simply improving the reporting of any differences in laboratory studies rather than trying to achieve standardisation. Finally, a talk by Dr Gregory Paull from the University of Exeter, UK, presented an interesting discussion on the UK Home Office Breeding and Maintenance protocol for genetically modified zebrafish. This stipulates that zebrafish are to be kept only to a maximum of 18 months of age, after which they are required to be euthanised. Dr Paull highlighted the lack of data on whether this is consistent with the 3Rs and maintaining welfare standards if the zebrafish are healthy at 18 months of age and continuing to breed successfully. Moreover, this policy could be leading to more zebrafish being used for breeding and maintenance than is necessary. As I previously said, my talk opened the 3Rs session on Day 2. I used this opportunity to update delegates on contemporary definitions of the 3Rs and share resources and guidelines to assist with the design and reporting of scientific experimental studies that involve the use of zebrafish. I discussed how better reporting, more reproducible studies, and new methods and technologies contribute towards advancing scientific progress and ensuring the highest standards of welfare are applied. Following Dr Lawrence’s talk, I agreed that there was a lack of standardisation across zebrafish facilities, but I discussed that for improved translation, this shouldn’t necessarily be the goal. Instead, better reporting to ensure studies are reproducible, should be. In addition, following Dr Paull’s talk I agreed that more research was needed to determine the validity of not maintaining breeding zebrafish after 18 months of age. In my talk I discussed how if zebrafish are still healthy and breeding beyond 18 months of age, this would go against the 3Rs principle of reduction, as it would lead to more zebrafish being required for breeding. However, if maintaining the zebrafish for breeding beyond this age had a negative impact on experimental outcomes, e.g., by affecting the quality of offspring, then this would go against reduction because more zebrafish would be required to minimise variation, and there could potentially be an increase in attrition rates. It would also go against refinement, if the breeding zebrafish experienced any negative health implications from breeding beyond 18 months of age. Finally, best practice in zebrafish husbandry techniques is direct refinement, so this was an opportunity to share knowledge within the community. Research on zebrafish welfare is advancing quickly so EZHAM was an important opportunity for the zebrafish husbandry community to be kept up to date on best practice, particularly on evidence that has implications for the 3Rs. It was great to hear about recent advances in zebrafish husbandry and research and establish areas where more work is needed. I want to thank the Zebrafish Husbandry Association for awarding me the Advancement Fund, without which I wouldn’t have been able to attend the meeting.

Inside the Tank: A Peek into the Tecniplast Annual International Zebrafish Husbandry Course, 2023 Part II/III

By Admin ZHA • July 1, 2024
Top Tips from the Expert Speakers Tecniplast has put together a great team of speakers, who are very knowledgeable in the field of zebrafish husbandry, and who have an amazing wealth of experience in their roles. Not only that, but they clearly love what they do, and it was great to have the opportunity to… The post Inside the Tank: A Peek into the Tecniplast Annual International Zebrafish Husbandry Course, 2023 Part II/III appeared first on Zebrafish Husbandry Association.

Inside the Tank: A Peek into the Tecniplast Annual International Zebrafish Husbandry Course, 2023

By Admin ZHA • June 7, 2024
Charli Corcoran Part I/III In October 2023 I was fortunate to attend the 10th Annual International Zebrafish Husbandry Course, hosted by Tecniplast and held in Buguggiate, Italy. The course brings together zebrafish husbandry experts from around the world to present recent advancements in zebrafish husbandry to the course attendees.  In 2023 the course ran from… The post Inside the Tank: A Peek into the Tecniplast Annual International Zebrafish Husbandry Course, 2023 appeared first on Zebrafish Husbandry Association.

A First Time For Everything (ZHA & AALAS) – by Mollie Millington

By Admin ZHA • December 31, 2023
Mollie Millington shares her experiences attending National AALAS The post A First Time For Everything (ZHA & AALAS) – by Mollie Millington appeared first on Zebrafish Husbandry Association.

Exploring the Wonders of Zebrafish: My Insights from the 10th Annual International Zebrafish Husbandry Course – by Candace Sparkman

By Admin ZHA • October 29, 2023
I was immensely fortunate to receive a $1000 grant from the Zebrafish Husbandry Association,which opened the doors for me to attend the 10th Annual International Zebrafish Husbandry Course in the enchanting city of Buguggiate VA, Italy, hosted by Tecniplast. From October 9th to 13th, 2023, I had the privilege of immersing myself in a world… The post Exploring the Wonders of Zebrafish: My Insights from the 10th Annual International Zebrafish Husbandry Course – by Candace Sparkman appeared first on Zebrafish Husbandry Association.

Advancement Fund Feature: Elizabeth Ibañez

By Admin ZHA • September 15, 2023
Firstly, I would like to express my gratitude to the Zebrafish Husbandry Association for the chance to further my knowledge in Zebrafish management and husbandry. The zebrafish program in our facility was started last year in March 2022, and the ZHA has provided great resources and connections that have furthered the success of our program.… The post Advancement Fund Feature: Elizabeth Ibañez appeared first on Zebrafish Husbandry Association.

The 2023 T-shirt contest is here!

By Admin ZHA • August 11, 2023
Our annual fundraiser has returned! Every year, the ZHA t-shirt design contest draws on the immense talent of our members to design a t-shirt for the membership (and even non-members!) to buy. The proceeds from the t-shirt sales go directly to our Advancement Fund program, which provides small grants to the membership to advance their… The post The 2023 T-shirt contest is here! appeared first on Zebrafish Husbandry Association.

Call for Abstracts: ANZAAP 2023!

By Admin ZHA • November 12, 2022
Call for Abstracts Closes 5th December With the approach of the 2023 ANZAAP Aquatic Symposium, we need you!!The 2023 Symposium will be a Hybridevent, hosted by Melbourne University and running over three days from the 8th to the 10th of February 2023.  We want to hear about what matters to you.Your research, your experiences, your animals, your successes and even… The post Call for Abstracts: ANZAAP 2023! appeared first on Zebrafish Husbandry Association.

The ZHA is Getting Recognition!

By Admin ZHA • September 14, 2022
The Zebrafish Husbandry Association (ZHA) is getting noticed: Lab Animal Europe, the leading publication for Scientists, Facility Managers and Technicians throughout Europe has just included a meeting announcement for the ZHA 1st European Meeting in its latest issue. Lab Animal Europe is circulated monthly and is packed with European content and topical issues, it is… The post The ZHA is Getting Recognition! appeared first on Zebrafish Husbandry Association.