Do the worms have forked tails.
If they don't have a forkted tail it could be skin flukes which cause bacterial infections on top.
Taken from this link.
http
/www.exoticpetvet.net/aqua/parasites.html
Monogenetic flukes are flatworms that are usually found as ectoparasites of fish. They often have a hooked attachment organ and they have a simple, direct life cycle. They are just visible to the naked eye. They often feed on skin and gill tissue, but usually only cause problems if found in large numbers. Gyrodactylus lives on the skin, fins and gills of many species of fish. This fluke gives birth to live young (others lay eggs). Clinical signs are "flashing" and skin problems. Treatment with formalin, praziquantel, TrichlorofonTM (dimethyl phosphate) or salt baths are effective. Formaldehyde is used as a bath for 12-24 hours at 20-25 ppm (mg/L), repeated every three days, for three treatments (same as for ich), with 30-70% water change in between treatments. Praziquantel is dosed as a bath for 3-6 hours, at 5-10 mg/L, repeated three times, with 30-70% water change between treatments. Praziquantel is now available in several commercially prepared tablets. TrichlorofonTM is used as a bath, for one hour, 0.25-1.0 ppm, repeated daily for three days, with 30-70% water change between treatments. Salt is used as a bath, as a 4-5 minute dip dosed at 30-35 g/L, repeated daily for three treatments, with a 30-70 % water change in between treatments.
Digeneans are endoparasitic flukes. They have two suckers, one at each end. They have an indirect life cycle, with fish acting as both intermediate hosts (carrying metacercaria larvae) and final hosts. Adult digeneans are usually found in the gastrointestinal tract, the larvae (which may be encysted) can be found throughout the body and cause problems if they invade such organs as the eyes (as does Diplostomum) or heart, in high numbers. The larval stages of digenetic fluke parasites (Clinostomum, Posthodiplostomum and Diplostomum) cause black spot in aquarium fish. Praziquantel is the treatment of choice. As a bath, for 3-6 hours, it is dosed at 5-10 mg/L, repeated for three doses, with a 30-70% water change between dosing. Praziquantel may also be dosed in the feed, at 5 mg/kg of fish, or it may be injected intraperitoneally or intramuscularly, dosed at 5 mg/kg.
