The signs of Piscene Tuberculosis can include:
Wasting disease. typically pinch bellied and from the front or rear the "back steaks" are concave rather than convex.
Bent spine or bone deformities.
Ulcers or open wounds.
It can attack the liver and cause swelling like dropsy.
It can attack the ovaries and stop egg production.
It breaks down the imune system so can make the fish more prone to other diseases.
It can therefore be difficult to diagnose because most of these signs can also be something else.
It is caused by a bacteria and is zoonotic---that is can be transmitted to humans (generally through cuts or broken skin on the hands). This is the main reason for the requirment to wear long waterproof gloves when quarantining fish.
If they do not improve after deworming that would be my next choice.They are gram positive micobacteria and they are slow growing and have a protective slime coat, both of which make for difficulty in treating with antibiotics. When I imported goldfish one type came up with PTB and Maf (in those days) took them away to be destroyed, they did not suggest a treatment. The fact that they took away the wrong fish is another issue for another day.