Effects of Replacing Commercial Fish Meal With Invasive Suckermouth Catfish on Growth, Health, and Economic Performance of Climbing Perch Anabas testudineus

The introduction of invasive suckermouth catfish (SMC) Hypostomus plecostomus has greatly affected the freshwater ecosystems in Bangladesh, posing a significant threat to indigenous fish species. This species is not commonly harvested and consumed, sparking debate over whether to eradicate it from the natural waterbody or repurpose it beneficially. This study explored the feasibility of utilizing SMC as a partial or complete replacement of commercial fish meal (CFM) in the diets of climbing perch Anabas testudineus, assessing impacts on growth performance, whole-body composition, hematobiochemical parameters, intestinal and liver health, and economic viability. Five isoproteic (32% crude protein) and isocaloric (9% crude lipid) diets were formulated with varying SMC levels: (0% [D1, control], 25% [D2], 50% [D3], 75% [D4], and 100% [D5]) and fed to fish until satiety over 90 days. Diets D1–D3 significantly improved palatability, growth metrics (final weight, weight gain, and specific growth rate), and feed utilization (feed conversion ratio and protein efficiency; p < 0.05), compared to D4 and D5. Enhanced levels of white blood cells, lymphocytes, and platelets were also recorded in D1–D3 (p < 0.05). Blood biochemical parameters varied significantly across treatments (p < 0.05), but no specific trend was observed. Superior intestinal integrity characterized by abundant goblet cells, intact stratum compactum, and well-developed villi was observed in D1–D3, along with improved liver morphology, particularly in D3. Economically, D1–D3 treatments yielded better outcomes, including higher production, reduced feed cost, increased revenue, gross margin, return on investment (ROI), and profit index (PI). Overall, replacing CFM with SMC up to 50% proved effective, supporting optimal growth, health, and profitability in A. testudineus, while offering a sustainable strategy to mitigate the ecological impact of this invasive species.