Two computerised identifying databank of IEF protein patterns of respectively flatfish and roundfish species are presented. It was found that interspecimen similarity of the IEF patterns, as processed by digitisation, was always larger than interspecies similarity (except for two roundfish species), which allows for unequivocal authentication of unknown samples, as long as the authentic pattern is available in the databank, The databank was used to authenticate commercial frozen fish. Sometimes, authentication of frozen fish from species not present in the databank (e.g. Gadus macrocephalus) was assisted by high similarity to a pattern available in the databank (e.g. Gadus morhua). It is also demonstrated that IEF patterns available on the Internet can be and incorporated into that databank, This opens the possibility to set up an integrated databank, joining IEF patterns available in various laboratories. As commercial software is now available to access such integrated databanks in a Client-Server set-up over the Internet, the construction of such an integrated databank should be considered.