# Directive 2010/63/EU of the European Parliament and of the Council of 22 September 2010 on the protection of animals used for scientific purposes (Text with EEA relevance), Division 11.2: Oxygen, nitrogen compounds, pH, and salinity

Extent: E+W+S+N.I.

Oxygen concentration shall be appropriate to the species and to the context in which the fish are held. Where necessary, supplementary aeration of tank water shall be provided. The concentrations of nitrogen compounds shall be kept low.
The pH level shall be adapted to the species and kept as stable as possible. The salinity shall be adapted to the requirements of the fish species and to the life stage of the fish. Changes in salinity shall take place gradually.

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Source: https://www.legislation.gov.uk/eudr/2010/63/annex/III/section/B/division/11/division/11.2 (the official version)
Page: https://openlegislation.uk/eu-directive-2010-63/annex-III/section-B/division-11/division-11.2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.