We present new observations of Hα emission in the Hickson compact group 18 (HCG 18), obtained with a scanning Fabry-Perot interferometer. The velocity field does not show motions of individual group members but instead a complex common velocity field for the whole group. The gas distribution is very asymmetric, with clumps of maximum intensity coinciding with the optically brightest knots. Comparing Hα and H I data, we conclude that HCG 18 is not a compact group but instead a large irregular galaxy with several star-forming clumps.
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