The River Marlais, a tributary of the Tywi (Towy or Towi), has brown trout, sewin (sea trout) and salmon fishing. Please do not confuse with the Pembrokeshire River Marlais which is a tributary of the Taf, nor the other Carmarthenshire Marlais which is a tributary of the Loughor.
Image © Philip Halling and licensed for reuse under this Creative Commons Licence.