Recently, Wazwaz (2022) and Meng et al. (2023) have made some outstanding contributions to a (3 þ 1)-dimensional integrable fourth-order nonlinear equation in a fluid, which is:) with g, b and a being the real nonzero constants, v(x, y, z, t) denoting a real differentiable function of the independent variables x, y, z and t, while the subscripts representing the partial derivatives (Meng et al., 2023). For equation (1), Wazwaz (2022) has investigated the Painlev e integrability, lump and multiple soliton solutions, while Meng et al. (2023) has presented the special cases in fluid dynamics, bilinear auto-Bäcklund transformations, breather and mixed lump-kink solutions. This Letter, based on the work in Wazwaz (2022) and Meng et al. (2023), aims to seek an auto-Bäcklund transformation for equation (1), which is different from those in Meng et al. (2023).In equation (1) let us put the truncated Painlev e expansion, in a generalized Laurent series (Zhou and Tian, 2022;Zhou et al., 2023;Gao, 2023aGao, , 2023bGao, , 2023c, around a noncharacteristic movable singular manifold conferred by an analytic function c(x, y, z, t) ¼ 0, as:Letter to the Editor 3561