I would go for a pair of WC mokes or WC palmas complex, one or 2 would do fine. I keep my ery ery in a 70 with a 13 inch ropefish, 7 1/2 inch ornate bichir, 6 1/2 inch palmas beutt., and soon to be 3 more bichirs (Black Volta endli, palmas palmas, palmas polli). Some nipping happens but the bichirs are tough enough for it. I would go to JA and snag a moke or palmas as it will take a long time before a senegal can be big enough to not be killed by the wolf, unless you can find a large one
it's a 40 breeders so any WC bichirs aren't really the best options since they grow to 10 inches+.
Erys can be kept with bichirs that are the same size with each other. 4 inch senegals can be regularly found in most LPS. Drew, how big is that wolf?