Most likely some sort of fungus. U'll need to get some fungus cure (blue colour liquid.... mythelene blue).

Also for your Ps. Lombardoi "kenyi", make sure ur water pH is above 7. 7.4-7.8pH is ideal for the kenyi.

They're stroppy little fish so either pack them in very very tightly (ie many many fish) or put one male to about 5-6females in the same tank. If u put 2 males in the same tank, u're likely to get one dead. Males are yellow, females are blue.