Lol, sorry to say this but I would ditch the tigers and dorado too. Goliath Tigers get over 4 foot, Dorados get over 3 foot. Instead, maybe get two-three more payaras
I've never heard anyone raise a Goliath tiger in any tank to 4ft size or a Dorado to 3ft. In a 8ft long 2.5' wide tank he's got plenty of time if ever they reach that size in a tank.