Drain tuna in a colander and shred with a fork until no clumps remain.
Transfer tuna to a medium bowl.
Add salt and pepper (approximately ½ tsp salt and ¼ tsp pepper), celery, onion, pickles, garlic, eggs and parsley until evenly blended.
Fold in mayonnaise and mustard and until evenly incorporated.
Refrigerate for up to 3 days.