A 2.7-km canalised section of the Kallang River, a major storm-water drain and reservoir spillway in Singapore, was rehabilitated into a 3-km naturalised, meandering river between 2009 and 2011. A combination of plants, natural materials, and civil engineering techniques were introduced to soften the edges of the waterway, to give it a more natural appearance and prevent soil erosion. Baseline data and published evidence of enhancement of aquatic biodiversity in this naturalised urban waterway are lacking, as there have not been any comprehensive biological surveys of the system to date. To determine the effect of rehabilitation, we quantitatively compared the fish assemblage and abiotic variables in the Kallang River after its rehabilitation (re-named Kallang River at Bishan-Ang Mo Kio Park or KRBAP; 2016–2018) against a downstream unrehabilitated section of the river (Kallang Canal; 2012). Secondly, we qualitatively compared fish assemblages and abiotic variables at the KRBAP and the Kallang Canal, to their source (upstream) reservoir, as well as to natural forest streams in close proximity. The KRBAP has a unique fish assemblage, which is dominated by two non-native cichlid taxa (quetzal cichlid, Vieja melanura (68%) and tilapia, Oreochromis spp. (17%)). Fish species richness (p < 0.001) and the percentage of native species (p = 0.015) was significantly higher in the KRBAP compared to the unrehabilitated canal. Moreover, the abiotic variables at the two sites are also significantly different. The fish assemblage and abiotic variables at the KRBAP resemble those of its (upstream) source reservoir, but contrasts with those of nearby natural forest streams. The unique fish assemblage in the KRBAP is shown to be stable, with similar species captured in high abundances across the three sampling years post-rehabilitation. Given the stability within the rehabilitated stream, further research and monitoring are needed to determine the established food web and predict the possible influence of future non-native species additions.

加冷河的一条2.7公里长的运河段是新加坡的主要雨水排放和水库溢洪道，在2009年至2011年之间被修复成一条3公里长的自然曲折河道。植物，天然材料和土木工程的结合引入了一些技术来软化水道的边缘，使其外观更加自然并防止水土流失。由于迄今为止尚未对该系统进行任何全面的生物学调查，因此缺乏关于该城市化自然水道中水生生物多样性增强的基线数据和公开证据。为了确定修复的效果，我们定量比较了修复后的加冷河中鱼类的组成和非生物变量（在碧山-Ang Mo Kio公园或KRBAP中更名为加冷河；2016年至2018年）在河的下游未修复部分（加冷运河; 2012年）。其次，我们定性地比较了KRBAP和Kallang运河的鱼类组合和非生物变量，它们的源（上游）水库以及附近的天然森林流。KRBAP具有独特的鱼类组合，其中以两个非本地丽鱼科鱼类群（格查尔丽鱼科鱼，Vieja melanura（68％）和罗非鱼，Oreochromi s spp。（17％））。鱼类物种丰富度（p  <0.001）和本地物种百分比（p = 0.015）在KRBAP中明显高于未修复的根管。此外，两个位置的非生物变量也存在显着差异。KRBAP的鱼类组成和非生物变量类似于其（上游）源库的鱼类组成和非生物变量，但与附近的天然林溪相反。KRBAP中独特的鱼类组合被证明是稳定的，在修复后的三个采样年中，相似的物种被大量捕获。考虑到修复后河流的稳定性，需要进一步的研究和监测来确定已建立的食物网，并预测未来添加非本地物种的可能影响。