Hi Petercar:
Yes, I have a garden eel. Mine is a spotted garden eel and I have had him for just over 2 years. I got him from Big Al's who told me they are easy to care for. I was very new to the saltwater tanks at the time and didn't know that they were on the expert care level list. (I have had wonderful beginner's luck with him) He used to eat cyclopseese all the time because I had him in with small seahorses. I found out he shouldn't be with seahorses so I started a reef tank this year for him when I got my new seahorses. He is now happily eating P.E. Mysis. I used to target feed him and still do if he makes a home in an out of the way spot with poor flow but I rarely have to now. Every few months he moves home as his old one gets soiled.
I tried getting some other garden eels to keep him company but they kept finding a way out of the tank even though it was covered so I gave up, then found out that the footprint on my seahorse tank was much too small for a second Garden Eel. They apparently need to have about 14" space between each eel. They are apparently territorial and only move their homes closer to each other if they are male and female. They need a deep sand bed or they can hurt their tail. My sand bed at present is about 4-5" but should be deeper. They are timid so don't do well with aggressive fish because they are afraid to come up and eat.
On the whole, he is my most long lived salt water fish and I love him to bits. He has put up with all my beginner learning and with a 2 month sojourn in a 10 gal tank while I dismantled my seahorse tank and got the reef tank fully cycled. He is now happily living in the reef tank with a Copperband Butterfly, some Chromis, PJ Cardinals and Neon Gobies. He hid from the Copperband for a while but has now moved home to the front of the tank and comes up nicely to eat. I have plans to get another spotted now that the footprint of the reef tank is bigger and hope the new one won't try to jump ship. My recommendation is to have a covered tank and plug any tiny holes around pipes coming out of the top of the tank, etc. if you do want one. Good Luck, they are wonderful fish.
Here is a picture of mine:
