Slim,
Bala Sharks can reach up to 14 inches in length
Irridescent Shark can reach up to 52 inches in length
You already have 2 catfish that are approximately 4 inches in length which I beleive are Pictus Cat and can reach 10 inches in length
Swordtails can reach 5 inches in length
Tigger barbs can reach 3 inches in length and are best kept in groups of 3 or more as they like to school together.
So as you can see you will eventually need a much bigger tank than a 20 gallon for these fish.
