In mouth-brooding fishes, there may be a trade-off between respiratory function (gill size and shape) and reproduction (space in the buccal cavity for offspring) during periods of parental care. This trade-off may become particularly apparent under low-oxygen conditions if a mouthful of eggs compromises respiratory pumping. In this study, we compare gill size and position among five males, ten brooding females, and eight non-brooding females of the African cichlid, Pseudocrenilabrus multicolor victoriae collected from a hypoxic swamp in Uganda. Brooding females exhibited a smaller total and average gill filament length than non-brooding females and males and a more elongated arch that may relate to spatial constraints imposed by the young. Importantly, brooding females also exhibited smaller overall hemibranch surface area than non-brooding females and males. In conjunction with earlier studies on this species that have reported a higher metabolic rate, higher aquatic surface respiration thresholds, and deeper ventilations in brooders, we suggest that the smaller gill size in brooders may reflect spatial accommodation and reduced respiratory function associated with parental care.