planting the tank would be a good idea, make sure it's w/ fairly hearty plants such as crypts, swords, Valseria, anything with a good root system. or take a peice of driftwood and attach some java moss, java fern to it. make sure you use a fine gravel, non-silica based sand type substrate. my guys kept with a colony of fancy guppies, he picks off some of the fry but they make for a nice compliment to eachother. the guppies always swimming unafraid seem to help draw him out more. I'de avoid anything really flighty such as many tetra species. I also keep a pair of clown plecos in the tank and they do not bother my peacock, and vise versa. 'cept i think they where mateing 'n chased him out of a hide spot. he's now taken residence in the java moss, opposed to under the driftwood where the plecos are.
anything non-aggressive, and not easily spookable is an ideal tank mate. other bottom dwellers are okay, as long as you have enough hide spots for everyone, and you avoid more predetory pleco species if you want one. They tend to suck slimecoats, and a scaleless fish like a peacock would be a prime target. CAE would be a huge no no w/ your eel. But clown/peppermint plecos would be fine imo.
