neither one of these guys is considered a tank mate they are solo flyers any tankmates are going to be food. as for price the cheapest I have seen is $60 up to $150 I got mine from aquascape and I have also seen them on aquabid.com but they are hard to find. I know from experience i have a 2 footer who has eaten 2 aro's and a pike and black convicts etc. too long of a list.. Also go to mfk articles about the 50000 gallon tank there are two full size leeri in there and a couple of full size arapima and the owner says the leeri attack the arapima. And as far a personality none my 2 footer does not have one at all I have had him 8 months or so and still cannot hand feed him. He tries to bite me so if your lookin for a personality wallago is not the way to go.