Hello! Many months ago my two goldfish had fin rot. They are about 7-8 inches long, excluding tails. I treated them with Maracyn/Maracyn 2 and Melafix and they seemed cured. I felt they developed fin rot because I was letting the water quality slip with infrequent water changes. Since the fin rot episode, I have been FAITHFULLY changing water, every week at 70%. My fish seem happy and I never had a problem with them other than this fin rot.

Needless to say, my parameters in a five year old 30 gallon tank with a Penguin 330 filter are -

NITRATE: 5
NITRITE: 0
AMMONIA: 0

My KH is almost non-exixtent at 2. This is after a 1/2 teaspoon addition of baking soda. (I was adding more baking soda to get the KH to 7, but it made my pH go into the 8.0's.)

My pH does drop a bit over the week, usually 0.02. Before this week's water change, it was 7.2. With the baking soda, it is 7.6 My tap pH was 7.0, now it is 6.8 (?). (My neighbor is having pH problems too.) I use Stress Coat water conditioner.

My current tank temperature is 76 degrees.

The goldies again developed fin rot, about 2 months ago. I cut back on the baking soda and added Melafix. That seemed to cure it.

Then the rot came back again. This time, I lowered my tank temp to 74, from 78. This seemed to cure the rot again.

With the summer weather, my tank temp is creeping up to 76. And guess what is back again?

The fin grows, but then is slowly starts to melt away or get holes it the newly grown fin. Also thin red veins start to streak the tails.

Am I right that I have fin rot? I bought another course of treatment of Maracyn/Maracyn 2 but haven't used it yet thinking high water quality would be the cure. I just don't know what to think or what to use.

I'd appreciate your input and suggestions.

You are right, good water quality is generally the best cure and prevention.

The only thing that's a bit out of wack atm is your pH, it keeps changing and this can cause split fins and red streaks.

My preferred method is to use a commercial pH buffer such as Prime Gold Buffer. The result is a consistent pH with no ups and downs.

It certainly sounds like Finrot to me and Maracyn should take care of it.

Finrot is usually caused by poor water quality. It sounds like your params are good except for the ph. Ph of 6.8 is too low. The overall ph issue is concerning...fish don't like unbalanced ph....even when you are intentionally changing your ph, it is advised to change it very gradually. This up/down effect could be stressing them out and weakening their immune system. If your ph is changing that often out of the tap, you may need to get a ph adjuster (not sure where you live but by me they actually have solutions called Ph Up and Ph Down). Goldfish can live in a pretty wide range of ph but the ph needs to remain stable....I would honestly try to get it up a little bit (but again, not all at once). My ph holds steady at 7.4

Thanks for the quick replies. The tap water pH is 6.8. I make sure the tank is at least 7.2. Sometimes it is 7.2, 7.4 or 7.6. I asked my neighbor if he was experiencing pH problems in his tank. He told me yes, so that is when I decided to retest the tap pH. Sure enough, it used to hold steady at 7.0 and all of a sudden it is 6.8.

I will buy a pH buffer or "hold steady product" ASAP.

1. What is the perfect pH for goldies?

2. Do you think the rising temperature has anything to do with the fin rot or is the fluctuating pH to blame?

3. Should I use the Maracyn/Maracyn 2?

4. Should I use Melafix?

5. Salt?

It is driving me nutty to see the melting fins. Thanks again.

A good pH for goldies is in the mid 7's. There is no reason for concern if the pH fluctuates a point or 2, like from 7.2 to 7.4.

Fluctuating temps that occur with seasonal changes can initiate all types of diseases in tanks, so that is another possibility but a lot of times these temp changes can't be helped.

I would first stabilise your pH, and this needs to be gradually, no more than a .5 jump per day. Once this is under control I would suggest a combination of melafix and just .1% salt. I don't think you have a rogue bacteria in your tank that needs the heavy medication, your fish are just reacting to the variable water conditions. Good luck.