There’s a decent chance your other fish can be infected as well. I would keep a close eye on their condition. Use your main tank as a quarantine tank for the time being and be prepared to provide treatment if necessary. You should be alright with some levamisole and scalpel
Possibly!
.... What appeared on your fish was a cyst-like thing with 2 wormy inside, somebody suggested parasitic nematodes.
Well, it is possible those "worms" were not worms after all, but a weird type of parasite of fish.
If interested, You be the judge - see this 2015 paper that describes infections on cardinal tetras. The fist paragraph of the introduction, and a clip of a figure (Clipped from Langenmayer et al., 2015).
The wormy things can be seen in the figures, A, B)
The following is from a research paper about juvenile catfish in China infected with dermocystidium:
Infected juvenile southern catfish were emaciated, and swam sluggishly on the water’s surface of net cages in the river. The infected catfish were covered with structures looking at first sight like white worms or winding white threads, which were subcutaneous (Figs. 1 to 3). Closer examination showed these structures to be cysts of the Dermocystidium sp., which were only observed in skin and fins of the catfish, and were not found in other organs. Cysts of different sizes (3 to 20 mm in length and 0.15 to 0.35 mm in width) were located in the dermis in an irregular way (Figs. 1 to 3). The anal fin was often found to bear cysts (Fig. 3). The infected sites of the fish skin displayed hyperaemia and oedema (Figs. 1 to 3). The epidermis at some parasitized locations was ruptured and had been shed (Fig. 2).
