Help For Rhombeus

This could take longer than 4 days to treat / heal. It could be a birth defect, or an internal parasite.

You could try something like Seachem ParaGuard or an internal parasite treatment.

This could be:
A small bird parasite that uses the piranha or any other fish for that matter for a secondary host. Eventually they hatch out and cause the fish no harm.They may look unsightly but they pose no threat at all to the health of your fish. No medication I know of will kill them and they will eventually go away.
http://www.piranha-fury.com/pfury/index.php?/topic/9129-black-spot/

this is from another person on this forum and it is accurate...as i have witnessed this on my Catoprion mento and wild caribe i had 10 years ago...and it goes away...i did add aquarium salt and upped the temp in hopes to speed up recovery..

I hope it s nothing bad thanks!!

no...just keep water clean and feed properly and he should be good

How is the fish doing?

id use pimafix and melafix for min of 10 days ( dont forget to remove carbon from filter) ,

on other hand id feed him some pellets with garlic as ingredient ,i am big fan of new life spectrum and they kept all my fish nice and healthy ( not trying to promote anything , just pointing out what i do)

let us know

Thanks for the tips the spots is the same but the fish eat every day and saw ok