Small ones love frozen bloodworms, when they outgrow those nightcrawlers are good. You should be able to feed NLS pellets as a staple diet. The tire track I had was years before they were available, but I have 2 Tanganykian spiny eels now that eat the 1mm cichlid pellets along with the rest of the fish.
Only bad thing about tire tracks, when they get large the pattern fades out, and they're a plain muddy brown fish.