Mark on Keyholes head

[BigBen]

Small variation in sizes and not round

[black ghost]

Not whitespot then. Possibly epistylis.
Epistylis is a relatively harmless protozoan that feeds on bacteria on the surface of the fish. It’s common in tanks with areas of low flow, where you’ll often find it in the glass.
If it is epistylis it means your keyholes have a bacterial skin presence. You’d need to treat with a bactericide, then the epistylis will leave the fish.

We’re they showing stress markings before or is it just now?

[BigBen]

The past couple of days with the colouring. If it's a protozoan, is protozin the right treatment still? There is little dots at the back of the tank below the filter outlet.

[black ghost]

Protozin will kill epistylis, or any other protozoan if it isn’t epistylis.
Myxazin will kill the bacterial skin ‘infection’ if it is epistylis.
I’d do P and then see if the fish need the M.
P has a bacteristat, that stalls they’re advances.

[BigBen]

Thank you!

[BigBen]

I started the protozin treatment yesterday and this is the results today

[black ghost]

Wow. It’s good stuff, eh?

[BigBen]

Wow. It’s good stuff, eh?

The last time I used it would have been about 12 years ago when I started out. I remember it being fantastic then!