Aquatic testing

We offer a wide range of aquatic tests and assessment services. These services include tests for all major types of aquatic products used internationally, toxicity tests to monitor the environmental impact of chemicals and disease challenges to support breeding programmes.

Disease challenge studies for selective breeding programmes

Our portfolio of reproducible aquatic disease challenge models and state-of-the-art testing facilities support commercial breeding programmes in investigating the genetic basis of disease resistance. Internationally recognised scientists work alongside highly experienced aquarists and statisticians to plan and deliver complex reproducible challenge trials. 

Test fish from the breeding programme are received into Cefas’ Aquatic Production Unit (APU) where they are reared in pre-determined family groups under tightly controlled and reproducible environmental conditions. Manipulation of tank parameters, such as photoperiod and temperature, according to established growth profiles, generates multiple test groups, allowing the inclusion of smaller scale preliminary range finding challenges where necessary. 

Challenge models are available for a wide range of fish diseases in a variety of host species, both freshwater and marine. Challenge methods include immersion, injection (intraperitoneal and intramuscular) and cohabitation (direct and indirect). Over many years, these robust challenge models have enabled Cefas to successfully support fish producers in numerous extensive breeding programmes, yielding invaluable results for the aquaculture industry.   

Disinfectant testing including BS EN 1656/14765

Cefas has extensive experience in the development and assessment of aquatic products, including disinfectants. Our highly skilled, internationally recognised scientists are supported by world class accredited testing laboratories, including tissue culture and media preparation facilities. We have an extensive in-house collection of bacterial and viral isolates, established over many years of research, including type strains and field isolates.

Effective disinfectants are vital in the prevention and control of aquatic disease. Our experienced researchers have outstanding knowledge of disinfectants and test methods, and can offer advice on the most suitable study design. The aquatic product evaluation team offer a wide range of suspension and surface tests on both bacterial and viral fish pathogens, from initial range finding, to more complex bespoke testing of bactericidal and/or virucidal activity. 

In 2010, a voluntary listing scheme was announced for aquaculture disinfectant products intended for use in the UK (Verner-Jeffreys et al., 2009). Having led the development of the scheme, Cefas’ scientists have expert knowledge of the testing methods required to obtain product approval. Experienced researchers will test your product according to the stringent criteria of the modified European standards, EN 1656:2009 and/or EN 14675:2006. All tests are audited by Cefas' Quality Team as required by the scheme. Further information on the listing scheme can be found at

Ecotoxicology testing

Our ecotoxicology team has more than 30 years' experience and operates at the forefront of freshwater research, studying the impact of chemicals in the environment. We are recognised leaders in marine and aquaculture science and have an extensive equipment pool and state-of-the-art research and tank room facilities. 

We have a broad customer base in both public and private sectors, providing services that range from routine toxicity checks to large multi-disciplinary projects. Our bespoke projects are developed collaboratively with our customers and could be focused on anything from complex effluents to environmental matrices. 

We also offer enhanced services identifying unknown causes of toxicity on aquatic organisms and assessing risks of various spills, discharges or other changing chemical influences. This research can include full environmental surveys if required. 

We regularly use a wide variety of scientific techniques, including:

  • Single-species standard acute toxicity tests
  • Sub-lethal toxicity assessments (e.g. on growth, reproduction)
  • Cell-based screening assays (e.g. yeast assays, DR-CALUX)
  • Toxicity identification evaluation
  • Chemical fate studies (including bioaccumulation and biodegradation)
  • Biomarker analysis in a variety of vertebrate and invertebrate species
  • Environmental surveys and monitoring
  • Desk-based chemical risk assessments
  • Consultancy on testing, regulation and chemical fate/effects
  • Passive sampling

Our bespoke service provision involves designing both marine and freshwater tests specifically to meet a client’s requirements. This includes model (e.g. OECD guideline 210: Fish, Early-Life Stage Toxicity Test) and non-model organisms (both fish and shellfish). Many of our bespoke projects use a multi-disciplinary approach, involving our chemistry, modelling and risk assessment teams. 

We carry out a range of toxicity tests, designed to monitor the environmental impact of effluent discharges, chemical spills or other activities that introduce chemicals into the environment. Our tests are carried out across a wide range of fish, invertebrates and other aquatic species, including: 

  • Toxicity in marine effluents, seawater and sediment
  • Benthic copepod (Tisbe battagliai) – acute 48-hour test
  • Pacific oyster (Crassostrea gigas) – 24-hour development test
  • Marine diatom (Skeletonema costatum) – 72-hour growth inhibition test
  • Juvenile turbot (Scophthalmus maximus) – acute 96-hour test
  • Mussel embryo (Mytilus edulis) – 24-hour development test, scope for growth and multi-drug resistance assay
  • Amphipod crustacean (Corophium volutator) – sediment toxicity tests
  • Marine worm (Arenicola marina) – sediment toxicity tests 
  • Toxicity in freshwater effluents, surface waters and sediment
  • Cladoceran (Daphnia magna) – 48-hour immobilisation test
  • Green algae (Pseudokirchneriella subcapitata) – 72-hour growth inhibition test
  • Juvenile trout (Oncorhynchus mykiss) – acute 96-hour test
  • Extracts/concentrates from freshwater or marine samples, for which we use in vitro assays, including:
  • YES assay – for oestrogenic and anti-oestrogenic activity
  • YAS assay – for androgenic and anti-androgenic activity
  • DR-CALUX – aryl hydrocarbon activity
  • ABC – antibiotic screening assay
  • Greenscreen – mutagenic activity

Direct Toxicity Assessments (DTAs) to measure the toxicity of complex industrial effluents. The resulting data is used to predict risks to the aquatic environment. The contaminants we have tested recently include:

  • Nanomaterials
  • Hydrocarbons
  • Oils
  • Pharmaceuticals
  • Pesticides
  • Metals
  • Oestrogens
  • Antibiotics
  • Flame retardants
  • Anti-foulants (including TBT)

Feeding studies including pharmaceutical additives

Fish feed can be one of the most significant costs for aquaculture projects. Feeds not only provide the nutrients for growth, but are also the delivery vehicle for important components, including additives (e.g. emulsifying and stabilising agents, vitamins, colourants and probiotics) and immunostimulants. Both feed additives and immunostimulants require regulatory authorisation before they can be marketed. 

Cefas has the staff, facilities and quality assurance procedures to provide experimental evidence of the highest quality for authorisation of new products, re-authorisation, or change of formulation. We can also help you navigate through the regulatory processes. 

We offer a range of services from simple in-vitro efficacy screening to in-vivo safety and efficacy testing. We can conduct toxicity, dose titration and residue depletion studies, (including radio-labelled marker residue studies). 

In-vitro efficacy arrays

The early stages of product development involve the selection of candidate products which show promising activity against targeted bacterial, viral or fungal pathogens. These candidate products can be of natural or novel chemical origin, or are sometimes compounds currently in use against different pathogens which require licensing for new purposes. 

Cefas’ customers in this area include aquatic product companies, veterinary pharmaceutical companies and disinfectant companies. We undertake this testing for our customers in our state of the art, fully-accredited laboratory facilities. Examples include:

  • Preliminary testing of the efficacy of candidate drug formulations for in-vitro efficacy against target organisms prior to selection for in-vivo safety or efficacy studies.
  • Determining the in-vitro activity of disinfectant products either as a pre-selection for novel products or to fulfil requirements for the voluntary listing of existing products on the Defra aquaculture disinfectant scheme.

Fish vaccine and veterinary product evaluation

We design bespoke studies for our customers, using a wide range of bacterial and viral challenge models. We can assist you in developing new candidate products regardless of the stage you’re at in the process, whether by conducting initial proof of concept scoping studies or studies for regulatory submission.

Cefas can help you develop pharmaceutical products, which are critical for:

  • Controlling the major bacterial and viral diseases in fish
  • Controlling sea lice infestations in marine fish farming
  • The development of antifungal agents

We also support alternative therapies, which have been developed as alternatives to antibiotics and chemical antiparasiticides, including:

  • Bacteriophage therapy
  • Immunostimulants
  • Probiotics

Our team of highly experienced scientists can design a bespoke study to meet your specific needs, based on your desired success criteria. We offer a full range of studies to evaluate your product from initial proof of concept studies through to regulatory testing, examples include: 

  • Batch release
  • Extraneous agents
  • Proof of concept
  • Safety and efficacy
  • Residues and depletion

Product safety and efficacy evaluations

We undertake testing on a variety of products for a broad range of private and public sector customers, including many major international animal health companies. Our studies primarily review either the safety or efficacy of specific medicines or products. 

Our internationally recognised team’s in-depth understanding and knowledge of the regulations for product compliance will ensure that your product is evaluated comprehensively. 

Safety studies

The process of obtaining marketing authorisation (MA) for new veterinary medicinal products requires extensive testing to demonstrate safety for the target host species and for the consumer under GLP and GMP compliant conditions. 

Cefas’ extensive capabilities in this field include: toxicity testing, dose titration trials and residue depletion studies (including radio-labelled marker residue studies). The Aquatic Product Evaluation team collaborate closely with the relevant regulatory authorities to assist clients in defining their success criteria. 

Efficacy studies

Cefas can assist at any stage of your product development, including determining efficacy. We have expertise in aquatic:

  • virology
  • microbiology
  • parasitology
  • ecotoxicology
  • molecular biology

Established challenge models include:


  • Lactococcus garvieae
  • Streptococcus spp
  • Renibacterium salmoninarum
  • Yersinia ruckeri
  • Vibrio anguillarum
  • Vibrio salmonicida
  • Aeromonas salmonicida
  • Moritella viscosa
  • Photobacterium piscicida
  • Piscirickettsia salmonis
  • Flavobacterium psychrophilum


  • Viral haemorrhagic septicaemia virus (VHSV)
  • Infectious haematopoietic necrosis virus (IHNV)
  • Infectious pancreatic necrosis virus (IPNV)
  • Spring viraemia of carp virus (SVCV)
  • Koi herpesvirus (KHV)
  • White spot syndrome virus (WSSV)
  • Salmonid alphavirus (SAV)
  • Carp edema virus (CEV)
  • Nodaviruses (NNV)


  • Sea lice (Lepeophtheirus and Caligus spp)
  • Amoebic gill disease (Paramoeba perurans)


  • Saprolegnia parasitica
  • Aphanomyces invadans

Available fish species

  • Salmonids
  • Cyprinids
  • Sea bass
  • Goldfish
  • Stickleback
  • Zebrafish
  • Amphibians
  • Other species of fish and crustaceans may be available on request

Residue depletion and radiolabelled metabolism studies

Residue depletion

Common EU harmonised legislation includes extensive and complex laws controlling the approvals of pharmaceutical and immunological products for use in veterinary medicine, especially for food species within the EU. 

Data for withholding periods for new pharmaceuticals is required as part of a dossier submission to gain market authorisation. Older data supporting drug withholding period claims may require replacement with modern data to ensure consumer safety. 

Cefas can deliver bespoke tank-based marker residue depletion studies to establish product withdrawal periods studies in accordance with VICH GL 48 guidelines. 

Incurred reference materials

Some countries from which the UK imports fish products have less rigorous aquaculture regulations than we are used to. This means that the use of illegal medicines in aquaculture remains a real concern. 

In order to confirm that standards are high, testing laboratories need access to incurred residue samples. These samples are produced by exposing live fish to potentially harmful substances, which allows proper validation of analytical methods. This enables us to reliably detect the presence of these harmful substances in fish meat. 

Cefas can produce samples of tissues in a range of fish and crustacean species, with the harmful residues present in the way that they are incurred in nature. 

Metabolism studies

For consumer safety, evidence must be produced to show that the proposed withholding period for new pharmaceuticals is sufficient to ensure that product residues (in fish this is in muscle and skin) will be below the EU-defined maximum residue level (MRL) at slaughter. The MRL defines, for foodstuffs of animal origin, the maximum level of residues that can be present without presenting any harm to the consumer. 

Cefas can deliver tank-based metabolism studies in accordance with VICH GL 46 guidelines, to determine the quantity and identify the nature of residues. Bespoke tank studies are designed to assess total radioactive decline of radiolabelled products (typically 14C or tritium) in a range of fish species. 

Our highly experienced scientists act as either study director or principle investigators in multisite studies that are Good Laboratory Practice (GLP) compliant. For metabolism studies we partner with analytical laboratories who deliver the radiobiological and chemical analysis.