72 gallon bow front tank with American cichlids and catfish.
Work your way up from small dudes to the big boys. More importantly, have the proper equipment and environment for your fish types.
6 Jack Dempsey, 5 Firemouths, 1 Peacock Bass, 1 Tiger Shovelnose Catfish, 1 Maganese, 1 Green Terror, 1 Brazilian Puffer, 4 Crayfish (1 blue), 1 Royal pleco, 1 Snowflake pleco, 1 Blue Phantom pleco, 1 King Tiger pleco
Plastic plants and bog wood.
When you see signs of stress in your fish, you can then take steps to identify the source of that stress and then to resolve it before it becomes a major issue.
If you're looking for a unique way to stock your new tank, give freshwater shrimp a try.
If your fish is suffering, you may want to consider euthanasia as an option to humanely end his pain.