Measuring plasma protein electrophoresis fractions and plasma concentrations of acute phase proteins (APPs) is commonly used to monitor inflammation and illness in mammalian species, but its use is not widespread in fish species, despite the presence of similar proteins. This study aims to determine plasma protein electrophoresis values for koi carp (Cyprinus carpio) and to assess the use of plasma protein electrophoresis and commercially available assays for 3 primary APPs (C-reactive protein, serum amyloid A, and haptoglobin) as markers of inflammation in 13 koi following invasive surgery. Median packed cell volume decreased by nearly 50% but recovered to baseline by 14 days postsurgery. Plasma protein electrophoresis fractions were consistent across the experimental period and did not demonstrate an inflammatory pattern, but electrophoretograms exhibited variation between individual fish. No clinically meaningful changes were observed in the APPs of the test subjects 28 days following surgery. Despite grossly evident inflammation of the incision line, either this surgical procedure did not stimulate a marked systemic inflammatory response, or the available assays are not effective in detecting the acute phase inflammatory response in this fish species.