Bile acids (BAs) are important amphipathic biomolecules that play a key role in the emulsification of lipids and consumption of other fat-soluble nutrients. While fat is an essential energy source for fish growth, excessive dietary fat induces degradation of growth performance, metabolic disorders, and fat accumulation. There is evidence that BAs can promote growth, accelerate lipid breakdown, and maintain bile acid homeostasis in fish fed high-fat diets (HFDs). However, the regulatory mechanisms remain unclear. This study aimed to explore the effects of dietary BA supplementation on BA homeostasis and lipid metabolism in juvenile largemouth bass (Micropterus salmoides) fed HFDs. Five isonitrogenous diets were prepared: a control diet (10.6% lipid, C), high-fat diet (17.53% lipid, HF), and HF diets supplemented with 300, 600, and 900 mg/kg BA (HFB1, HFB2, and HFB3). A 7-week feeding trial was performed, and all the fish were fed to satiety twice daily. Samples were taken at the end of the trial to detect growth and plasma biochemical parameters as well as lipid and BA metabolism-related gene expression levels. The results showed that HF diet significantly decreased final body weight (FBW), specific growth rate (SGR), and weight gain (WG) (P＜0.05). In contrast, the addition of BAs to the HF diets improved growth performance, with the growth of largemouth bass significantly increased when supplement with 600 mg/kg BAs (P＜0.05). Moreover, the lipid content in muscle was increased by the HF diet (P＜0.05) and was decreased by supplementation with BAs (P＜0.05). The HF diet increased the triglyceride (TG) contents in the plasma and liver (P＜0.05), while BA supplementation decreased both (P＜0.05). Furthermore, the addition of BAs significantly decreased the expressions of sterol-regulatory element binding protein 1 (srebp1), fatty acid synthase (fas), and acetyl-CoA carboxylase 2 (acc2) and increased the expressions of lipoprotein lipase (lpl), hormone sensitive lipase (hsl), and hepatic lipase (hl) (P＜0.05). Additionally, BA supplementation increased the expressions of carnitine palmitoyltransferase 1 (cpt1) and acyl-CoA oxidase 1 (acox1) (P＜0.05), yet had no effect on expression of peroxisome proliferator-activated receptor α (pparα) (P＞0.05). These results indicate that BAs increase lipolysis and fatty acid β-oxidation, while decreasing lipogenesis. Moreover, fish fed a BA supplemented-diet showed increased total bile acid (TBA) levels in the liver and plasma (P＜0.05). When 600 mg/kg BA was added, the expression of farnesoid X receptor (fxr) was also increased (P＜0.05). Therefore, BA supplementation increased the expressions of cholesterol 7 alpha-hydroxylase (cyp7a1), bile salt export protein (bsep), and apical sodium dependent transporter (asbt) via activating fxr (P＜0.05). In conclusion, dietary BA supplementation improved growth performance, lipid digestion and absorption, and bile acid metabolism by activating the bile acid nuclear receptor FXR. The effects and possible mechanisms of BAs on lipid and bile acid metabolism were also preliminarily revealed. This study contributes to our understanding of the role of BAs in lipid metabolism in teleosts and enriches our knowledge of bile acid homeostasis under different conditions.