HOLD up, u cant just go to the store and buy a whole bunch of fish at once. One at a time, and you have to wait at least 3 weeks b4 introducing another fish. The tank needs to mature to the new bioload and develop more bacterias, etc. So, if u bought the volitan a lil while ago, and it hasnt been atleast 3 weeks, then i wouldnt do it. And to answer your questions-> The chainlink eel and sfe ell will be fine. They are both the docilest of the eels that i know of, and they neither get too big, or aggressive, and they arent that picky with eating -> Trade the volitan in and get a fuzzy dwarf instead, while yer not yet attatched to the volitan. it WILL get too big for yer tank, and by then you'll be too attatched and force yerself to get a new tank for it. I know cuz thats wats happened to me. Not saying that its a BAD thing, but it did cost me another $400 more in order to set up the 120 gallon. You can keep a fuzzy dwarf and the two eels in their for life, no problem, with the proper filtration and care. But not a volitan. Just my advice. Now, dont go to the LFS just to BUY a fish cuz u can, u have to do this properly, or you can have problems. Take it slow, and you'll be successful. Anyways, have a good day.