Columbian Shark- Grey Spots (Help)

[Waterthoughts]

my dad's Columbian shark seems to have grey (the same color as his body mass) spots on his stomach and bottom torso.
i thought i might be Velvet (Oodinium), but the description online made me think other wise......

what do you think it could be?

 

[ceeej31]

is it in full freshwater?
they need brackish and develope skin conditions (like the one you describe) when kept in full fw

 

[Waterthoughts]

the tank is freshwater right now, they are only juviniels. i did hear that when they get big they should be moved into brackish.
the tank has salt in it right now, its has been since they've been in there too....

should i do something different right now?