When Sam sees the fish tank he identifies the clownfish (the black and yellow fish) and comments on how hard they are to keep.
Clownfish aren't hard to keep. There are a few different species of tropical saltwater fish in the tank and out of all of them they are actually the easiest to keep and require the least care.
In the opening, the 2 gunmen crashed their motorcycle into a blue car, which got dented really bad & there were broken pieces of the car hanging off. When the CCTV of the accident was reviewed at NCIS headquarters, it showed them crashing into a burgundy colored car & no dents were made & no broken car pieces.