it is 8x2 so I’m not getting the gar but do you have any other suggestionsA lot of unanswered questions here. Tank is 250 but what are the dimensions? What are the avarage adult sizes of the fish you'd like to keep? If say the tank is 8×2 then I think both of your main fish ideas will be a no. I haven't owned pbass I don't care for how they look so I don't know exact adult size but I think 20" isn't impossible. That would give the fish 4" front to back imo not enough. I know the gar can easily exceed that length so again no.