Redclaw (Cherax quadricarinatus) are a species of freshwater crayfish native to Australia and have been farmed since the 1980s. However, the industry is still small and a major limitation to growth is the lack of a commercially available feed formulated for redclaw. The aquaculture industry is increasingly using less fishmeal in feed, often substituting with plant based protein sources. The suitability of an ingredient requires determining its digestibility, this is important for feed formulation as it quantifies the potential availability of nutrients that can be absorbed and utilised to support metabolic process such as maintenance, reproduction and growth. Determination of diet digestibility and performance of fish in feeding trials are standard. However, there is the assumption is that the animals being used in experiments are healthy individuals. In crustaceans, such as redclaw, signs that an individual is compromised is sometimes only apparent upon refusal to ingest feed or sudden death. External signs such as marks or discoloration on the exoskeleton are not useful identifiers. Nutrient absorption and secretion of digestive enzymes for crustaceans occurs in the hepatopancreas with changes structure reported to occur from changes environmental conditions, different diets and feeding regimes. A digestibility study on redclaw fed a variety of plant based and animal-rendered products showed diet related effects upon examination of the hepatopancreas. A number of structural abnormalities were observed including: degradation of the myoepithelial cells, sloughing of cell contents, hypertrophy of b-cells, and thinning of epithelial lumen. Additionally, granulomas, bacterial, and viral infections (CqBV and reovirus) were also present. The study raised questions as to the potential effects of ingredients for long durations and the importance of using multiple disciplines to assess diet performance in redclaw. It is clear that there needs to be a greater awareness of the known viruses and diseases that are present in redclaw populations when conducting nutrition studies. Recommendations on the use of ingredients are often supported with performance parameters, such as growth and survival; however, this ignores vital information. Histological examination of hepatopancreas is an important technique to consider in nutrition studies. It is a well-established but often overlooked method that is simple to implement and can provide a greater understanding of the health of the animal in relation to diet.