Slice each carrot in half widthwise then in half again lengthwise. Slice each quarter into three wedges. Place carrots into large jar. They should all fit snuggly standing up in the jar.

Warm water, apple cider vinegar, sugar, garlic, dill seeds, fennel seeds, salt and sliced serrano in a medium saucepan over medium-high heat. Bring to a boil then reduce heat to low and simmer for 3 minutes. Carefully pour hot pickling liquid over the carrots. Add fresh dill to the jar, secure the lid and let sit for 1 hour before refrigerating. Let the pickled carrots sit in the refrigerator for at least one day before eating.

Carrots will keep for 2 to 3 weeks in the refrigerator.