Healthy and active? No worries! Daschunds come in different sizes, and your little doggie may be a miniature .. or, have some miniture daschund in his genetic makeup. If his eyes are bright, he's alert, nose is cool and damp, he's OK .. but when you guys take him in for annual vaccinations, checksups, you can always talk to the vet about it, too :-)
BTW, if that's your doggie in the pic, he is a cute little fella :-)