Members of the freshwater catfishes (order Siluriformes) are capable of transintestinal expulsion of foreign bodies, including internally implanted tags, which can bias movement and survival estimates. We evaluated long‐term (120‐week) retention rates of passive integrated transponder (PIT) tags in a laboratory setting to assess potential tag loss in Stonecat Noturus flavus. The PIT tags were surgically implanted into the peritoneal cavity of fish (n = 157) ranging from 71 to 213 mm TL. We demonstrated that Stonecats can successfully be tagged with 12‐ and 23‐mm PIT tags with low levels of mortality (5.0%) and tag loss (9.6%). Based on individual encounter histories and covariates, we further evaluated our data set in a multistate framework using program MARK. Based on our findings, tag age has a negative effect on tag loss; if Stonecats lose tags, it is relatively soon after tagging. Additionally, Stonecat TL has a negative effect on tag loss, with tag loss decreasing with increasing fish TL.