Five species of the rock-climbing, gobiid subfamily Sicydiinae are now known from Ponape, Eastern Caroline Islands, Micronesia, four of which are described herein as new: Sicyopus nigriradialus, Sicyoplerus lividus, Sicyopterus eudenlatus, and Sliphodon caeruleus. This
increases the number of described freshwater/estuarine fish species from that volcanic island to 15. The fifth sicydiine species from Ponape, Stiphodon cf. elegans. is compared with other Pacific basin Stiphodon. Sicyopus fehlmanni is described as new from Babelthuap and
Koror islands, Palau, Western Caroline Islands, Micronesia. Sicydiinae Bleeker, 1874, is the valid name for this subfamily. The widely used name Sicydiaphiinae Koumans, 1931, is an improperly formed synonym of Sicydiinae. A newly described character to support sicydiine monophyly involves
relative position of the pelvic-fin spine and rays. A key to Ponapean sicydiines is provided.
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