We have used sequence information and gene location to identify NPY family genes in the pufferfish, Takifugu rubripes (fugu), and zebrafish. Fugu has two copies of NPY, presumably resulting from the ray-fin fish tetraploidization. Zebrafish has probably lost one of the copies. Both species have two copies of PYY, the second of which was previously named PY. The two fugu NPY genes are predominantly expressed in brain. The two PYY genes are expressed in a broad range of tissues including brain and gonads. Thus, the NPY system appears to be more complex in teleosts than in tetrapods.