Schiermonnikoog and Vlieland have a freshwater fish fauna with very few species. Actually only the ninespine stickleback plays a significant role there. In addition, on both islands also Prussian carp (a carp relative) are sometimes caught. The sweet waters of the other three islands are also inhabited by perch, roach, bream, silver bream, common rudd, carp and pike. The zander lives only on Texel and the tench only on Terschelling.
See also the table here.
This site says that the goldfish (domesticated form of the Prussian carp), probably released from aquariums, is the only freshwater fish of Vlieland.
- Dutch fish ladder for sticklebacks (dearkitty1.wordpress.com)
- Brent geese on Vlieland island (dearkitty1.wordpress.com)
- Patterns of Distribution of the Helminth Parasites of Freshwater Fishes of Mexico (plosone.org)
- Carp haul from south-west Qld waterways ‘incredible’ (abc.net.au)
- New wasp species discovery on Texel island (dearkitty1.wordpress.com)
- What freshwater seals eat (dearkitty1.wordpress.com)
- Dutch cormorants already have eggs (dearkitty1.wordpress.com)
- Our Not So Fishy Future (economistsview.typepad.com)