Trying to identify a fish

Question
QUESTION: Hi,

I was visiting my uncle for Thanksgiving and he has a fish he has had for 15 years and said he couldn't recall what type of fish it is.  It is in a saltwater tank and is a very long, eel-like or ribbon-like fish, it does have fins behind it's head and he said that is why it is a fish not an eel.  It has a long dorsal fin and sort of looks like the pictures of dragon gobies I've seen.  It is black and yellow striped (not striped front-to-back but circular stripes and could swim either forward or backward.  He said when he bought it, it was about 1.5" long and now it is 8" or so long at ~15 years old.  It has a large mouth.  He said it will kill other fish he's put into the tank with it, even of the same species.  It likes to dig in the substrate.  It likes to hide in a rock cave in the tank.  He said they're rare and you don't normally see them in pet stores.  I hope I have given enough description to identify the fish.  Thanks!

ANSWER: Hi Kristen

Unfortunately without a good picture it would be nearly impossible for me to identify.  Is it possible for you to get me one?

Cheers

Michael

---------- FOLLOW-UP ----------

QUESTION: Hi Michael, thanks for the fast reply!  I'm not sure I can easily get a picture since we aren't there often, BUT I just spent a good deal more time looking and I am 98% sure it is an "engineer goby", or a "convict blenny" depending on what you would call it.  It was a very cool fish and looked just like the pictures I found.  I used this link to identify it www.austmus.gov.au/fishes/identify/index.cfm .  Are these commonly kept?  They certainly don't have them at PetCo!  Thanks again!

Answer
Hi Kristen

I can now see the resemblance between the engineer goby (Pholidichthys leucotaenia) and your description of your uncle's specimen.

More details can be seen here:

http://www.wetwebmedia.com/pholodichthyidae.htm

Also from my own further reading of this species, it is not very common in the marine aquarium trade.  Not rare, but certainly not common.

Thank you for bringing this species to my attention.

Kind Regards

Michael