Fish Mox to control Fin rot

Once again I'm battling a disease in our aquarium. This time its fin rot on one of our goldies and it seems to be getting progressively worse.The others are fine (rosy barb, another goldy, white cloud minnow). Every 4-6 weeks we have something that appears in our tank. This can't be normal and is probably something I'm not doing right.

Kokos goldfish forum says that fin rot is due to a bacterial infection which is caused by bad quality of water or overly stocked aquarium.

I've only just discovered that my tap water contains lots of choloramines (i assumed it was cholorine) and when treated with API tap water conditioner this converts to large amount of ammonia. I prepared a fresh batch of water as I normally do and tested this for ammonia. I found it contained 0.5ppm of ammonia and is similar to what other people in my area are reporting too. Maybe this is the cause of the bad water quality issue we are having?

For the next water change I'm going to buy some API Ammo-lock and use this in conjunction with my API tap water conditioner. When this combo runs out I'm changing over to Prime as recommended by my LFS.

To treat the fin rot, I've already added 0.3% of salt to the tank (equivalent to 3 tsp per gallon) and after a week there was no change. Next I tried Aqua Master Tri Sulfa Tablets and Melafix with little improvement.

The preferred treatment on the Kokos list is Penicillin. Penicillin is synthetically produced where as Amoxicillin is a semi-synthetic penicillin drug. Amoxicillin might be considered an improved form of penicillin. So I'm going to try one tablet of Fish Mox Forte as we have a 20 gallon tank.

However I am going to use some "left over" human amoxycillin (amoxycillin sandoz). The human tabs are 1000mg so I'm going to dissolve half a tab in some aquarium water and see what happens.

Amoxycillin Sandoz tablets contain 1000 mg amoxycillin (as amoxycillin trihydrate) as the active ingredient. The tablets also contain the following inactive ingredients:
• magnesium stearate
• cellulose - microcrystalline
• povidone
• sodium starch glycollate
• titanium dioxide
• talc - purified
• hypromellose.


Update #1 : 19/9/12 10.30pm
I took 1/3 of a tablet (ie ~350mg amoxycillin) and dissolved it in some tank water. Like the Trisulfa tablets there was some residue left (cellulose material) over which I let fall into the tank as well.

I got nervous and couldn't put the half tab so the concentration is half way between fish mox and fish mox forte.


Update #2: 20/9/12 7am
All the fish are still okay. The healthy ones are still swimming with all the same vigor and energy as before. The affected goldy seems no worse off and doesn't look better either.

So according to the fish mox directions tonight I'm going to make a 35% water change (replacing the 0.3% salt) and add another 1/3 tab of sandoz.