First of all, with all due respect... I would not have used Mardel
Products (Maracyn, Maroxy, etc.) to treat ANYTHING!!! After having
worked in the aquarium trade for the better part of a decade now, and
at one point being forced to use Mardel medications on fish (and I
followed the package instructions to the letter)... My perception is
that Mardel medications have a ridiculously bloated price, are often
ineffective, or if they do have some effect, it is usually to cloud
your water and kill off most of your beneficial bacteria. In the
remote chance that they DO treat any diseases, it usually takes 3-5
times longer than many cheaper, safer, lower-dosage medications on the
market. If you need a recommendation on a cheap, effective
medication, instead use Pimafix (by Aquarium Pharmaceuticals)... it
is safe for fresh or sal****er, safe for inverts, and works VERY
quickly at clearing up most bacterial and fungal issues in fish. On
top of that it is plant-derived, not a synthetically-produced
antibiotic. Just remember that as with any medication, read the
instructions and follow them closely. I used this same product as a
last resort on a tank full of seemingly-doomed Discus that had just
about every known malady: no appetite, fin rot, cloudy bacterial
slime-coating, and were gasping at the surface of the water. Within
48 hours, most of their symptoms had cleared, they were eating
heartily, and were visibly gaining healthy body mass again.

Good luck to you.