Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
I'm not sure I understand what you are asking. Sirloin cap is beef and piranha is a fish. Are you asking how you would cook each? Or make a dish from the two together?
Can you please clarify?
Pat is a trusted home cook.
Did you mean picanha? Here's an article and recipe:
I Can’t Stop Feeding My Neighbor
Cooks Well Under Pressure
Triple Chocolate Mousse
A Better Way to Travel