Jardini are substantially more rare than silvers (still, neither are very rare), thus the higher price. If you're going to keep it with tankmates, go with a silver - there's no gurantee that the jardini won't kill all of your fish. The silver should be fine with the African tiger pike (Hydrocynus sp. or Hepsetus odoe?) and gar (provided they are close to equal size), but the eel should be in brackish water. I like jardinis a lot better, but like I said they don't do well with tankmates most of the time. $60 is a decent price for the jardini, at least if it's around 5"-6"... $20 is also decent for a silver if it's around 5"-6" as well.
