Questions about Freshwater Predators and oddball fish

[gmwJOY]

Q 1. is there any nano piscivore or carnivore fish species which is readily available all over the world ?
Q 2. 4 ft long tank pure predator fish recommendation but fish should be readily available all over the world. and some odd balls that can live with them.
Q 3. i love pink tail chalceus and hujeta gar rbut here where i live these fish is not available any alternative for them that can be easily found ?
Q 4. red tail cat fish alternatives for 2 ft tank that can be easily found ?
For life time keeping......................

thanks ...... Joy Banerjee from India Kolkata gmwJOY