Exogenous feed is the main source of nitrogen in catfish aquaculture production systems. Nitrogenous waste is excreted as ammonia by catfishes across their gills after proteins are broken down during digestion. If allowed to accumulate to toxic levels, high ammonia concentration can lead to reduced appetite, reduced growth, and possibly death. Excretion rates for catfishes may vary depending on different variables, including temperature, which was measured in this study. Channel catfish (Ictalurus punctatus) were fasted for 72 hours prior to starting the excretion trials and measurements taken at 48, 36, and 12 hours before feeding. The fish were 46% protein feed to satiation at timepoint 0. Measurements were started 2 hours post feeding, taken every two hours until timepoint 8, and then every 4-12 hours until 48 hours post feeding. The first trial of this study was performed at 25 °C, where excretion rates were significantly higher within 4 hours post feeding and peaked between 6-12 hours post feeding. Excretion remained significantly elevated until 32 hours post feeding. The second trial was conducted at 32 °C and excretion was significantly elevated within 2 hours post feeding, peaked between 6-8 hours post feeding, and concluded before hour 48. However, peak excretion rates at 32°C (44.9 ± 4.0 mg N/kg/h) were more than double that of the same fish at 25 °C (19.3 ± 2.2 mg N/kg/h). At higher temperatures, catfish nitrogen excretion increases sooner and to a higher rate after consuming a meal, but the duration of the postprandial response is the same.