Summary This study provides the length–weight relationships (LWRs) for four fish species [Leptobotia rubrilabris (Dabry de Thiersant, 1872); Opsariichthys bidens Günther, 1873; Xenocypris yunnanensis Nichols, 1925; and Sinogastromyzon sichangensis Chang, 1944] collected from the Niulan River, China. Samples were obtained between April 2008 and June 2011 using various types of fishing gear [drift gill nets (mesh: 5 × 5 cm), hook and electro fishing]. A total of 136 specimens belonging to four fish species were analyzed. For each species the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Prior to this study, the LWRs for S. sichangensis and X. yunnanensis were unknown. New maximum sizes for S. sichangensis and X. yunnanensis are also provided.

Summary Length–weight (LWR) and length–length (LLR) relationships are reported for Glyptothorax fokiensis (Rendahl, 1925), Microphysogobio kachekensis (Oshima, 1926), Pseudobagrus brevicaudatus (Wu, 1930), and Sinibrama taeniatus (Nichols, 1941) from the middle reaches of the Minjiang River and its tributaries, Sichuan Province, in southwest China. A total of 675 specimens were obtained between 2013 and 2016 using various types of fishing gear and electroshock fishing techniques. Standard length and total length for each individual were measured by digital slide caliper and each body weight was taken by digital balance. The b‐values for LWRs varied from 2.617 to 3.249 (r2 > .954), and the LLRs were highly correlated (r2 > .983; p < .01).