How to Prune Opuntia robusta?
No pruning required

Opuntia robusta · Opuntia robusta
Under glass grow in sharply-draining loam based compost (JI No2) with added sharp sand or perlite, or a proprietary cactus compost. Provide full light at all times and allow compost to dry before watering during growth period in spring, summer and early autumn and apply a balanced liquid fertiliser three or four times. Withhold water and fertiliser in winter when dormant. See houseplant cacti and succulent cultivation for further advice
No pruning required