Flukes come in 2 forms, external and internal, and there are several species. Hiding, rapid breathing discoloration are common symptoms of fish infested with flukes.
Several treatment options can be used including: copper and FW dips with or wo malachite/formalin. Flukes normally do not present as the contagious plague that you find in ick and velvet, and many flukes are specific to particular fish species.