They are probably something you should take back. They are banded pipefish, which are incredibly difficult to take care of. Pipefish are relatives of seahorses, and need to live in similar conditions, ie a well established tank with TONS of pods and other live food, and without other fish. They are slow swimmers, and get easily harrased. What kind of tank do you have them in? What other tank mates? I'm not trying to flame you, but please research before you buy things, these are not fish to be kept by the average person.