I've seen this before with my dats and it's deadly. Wiped out 90% of my dat collection. I tried melafix didn't work. I raise the temp to 90-92F and add salt about 2 tsp per 5g and my dats got cured in about 3 days.
Better separate that delhezi and and do some major water change in that tank as it might have already spread out. Any wounds or opening will get infected. The spores actually pops and spread out. Especially with no substrates it can easily be stir away.
Thank brutha, I'll go add some salt. I already treated the entire 150g tank with Parasite Clear. It was not fun that I had to run to Walmart @ 1:30am rushing to get meds. It had to be done cuz the sooner I treat it the better chance of curing I have.
I saw a delhezi for sale once that had one of those and it was still there a month later. The pimple had grown in size and turned red. Id reccomend salt and heat. If it pops then blast it with parasite clear. Fungus clear may also work but definitely Q tank him and look for signs on the other fish.