I haven't seen them there before. I don't usually check in on that big al's though. I find they usually have a worse selection than Oakville or Mississauga.
As far as something a little closer Petland in St. catharines have had the barracudas in the past. The local wholesaler that always used to carry the cuda species closed last year though so I'm not sure if they can still get them. I would ask, they might still be able to get something like that by a transhipment.
I don't know of any other shops in the niagara region that might stock the freshwater barracuda species.