Abstract: The present document is directed to probiotic bacteria and their use in fish farming for increasing the weight of fish and for treating and/or preventing a microbial infection of the fish. The bacteria are species within the Aliivibrio, Psychrobacter and Pseudomonas genera.

Abstract: A method for increasing the weight and growth rate of fish, preferably Salmonidae, and for preventing and/or treating microbial infections, comprising the steps of a) adding one or more species of probiotic bacteria to water, wherein the species of bacteria comprises or consists of Aliivibrio njordis, Aliivibrio balderis and/or Aliivibrio nannie; and b) exposing the fish to the water containing the one or more species of probiotic bacteria. Preferably, the bacterial strains Aliivibrio njordis strain B1-25, 8-1/2013 mandib V11, Aliivibrio balderis B1-24, 18-1/2013 kidn V12 and/or Aliivibrio nannie B8-24, 313/2013 kidn V13 are used.

Abstract: The present document discloses a new species of Aliivibrio, herein denoted Aliivibrio friggiae. A strain Aliivibrio friggiae, denoted Aliivibrio sp. 130206K7F2 506, has been deposited at the National Collection of Industrial and Marine Bacteria and has been assigned accession number NCIMB 42181. Further disclosed is the medical use of Aliivibrio friggiae for vaccinating fish against a new disease identified and herein denoted friggiosis.