These little guys are so difficult to photograph, I didn't get any photos of them on last years trip that I was satisfied with. This year I had much more luck :-D
Strawberry Poison-Dart Frog
Also known as the Blue Jeans Frog, they are the second most toxic frog in Costa Rica and they grow to approximately 17.5–22 mm in standard length. They are common throughout their range, which extends from eastern central Nicaragua through Costa Rica and northwestern Panama. The species is often found in humid lowlands and premontane forest, but large populations are also found in disturbed areas such as plantations.