Morphological Traits and Ecological Factors of Lacustricola centralis in the Cigongo Marsh, Kabare Territory, South Kivu Province, Democratic Republic of Congo

Wetlands are globally recognized as biodiversity hotspots, yet they remain among the threatened ecosystems. In the Democratic Republic of Congo, Ichthyological studies in wetlands are scarce, particularly in South Kivu, where anthropogenic pressures are accelerating habitat degradation. This study provides the first detailed morphological and ecological assessment of Lacustricola centralis (Seegers, 1996), formerly classified as Aplocheilichthys centralis, in the Cigongo Marsh, a wetland located in the southwestern watershed of Lake Kivu. A total of 249 individuals were sampled across four sites, and morphometric parameters (length and weight) and meristic traits (lateral line scales, fin rays) were analysed alongside physicochemical parameters. Size-class distribution was determined using Sturges’ rule, while Fulton’s condition factor (K) was applied to evaluate physiological status. Results revealed total length ranging from 16.8 to 50.8 mm and weight from 0.1 to 2.3 g. Lateralis line scales varied between 11 and 27. The sex ratio was female-biased (0.37 male: 1 female) with females dominating across size classes. Fulton’s K values indicate good body condition, with no significant differences between sexes or sites. Growth patterns were negative allometric, favouring elongation over mass increase. Physicochemical conditions were generally suitable for fish growth, though dissolved oxygen showed localized variability. The restricted distribution of this species, absent from Lake Kivu’s ichthyofaunal lists, highlights its potential as a bio-indicator of wetland health. These findings provide baseline data for ichthyofaunal inventories and support regional wetland conservation strategies.