I have a 20 gallon high tank with 7 Serpae Tetra, 3-4 ottos, a pair of kribs, and a clown plec. I realize that I am fairly heavily stocked. The tank is over a year old and it is fully cycled. ammonia, nitrite are 0. Nitrate is 20-30. kH is 1-2. pH is 7.0 to 7.5. I use an aquaclear 30 filter. It is a planted tank. No CO2 addition.

My one Serpae Tetra has a white face. It appears to be spreading very slowly back his body. It started at least 2 weeks ago. There are no other symptoms on the fish or any of the tankmates. It just lloks like he/ she is losing the color out of the scales. There are no stringy things or fungus. The fish eat peas, frozen brine shrimp, cucumber, a few varieties of flake food, freeze dried daphnia and tubiflex worms.

The white face fits columnaris, but his/her mouth and fins are 100% intact. I've also read that columnaris should take days or hours to kill the fish. Like I've stated previously the white face started 2+weeks ago.

Any ideas?

I have a hospital tank but it is housing my fry at the moment.

Columnaris not always a fast killer it depends on the strain of bacteria.
Anys signs of flicking and rubbing.
Columnaris can also look like bleached out patches beneath the skin.

No flicking or rubbing that I have seen. The fish did do one brief odd little wiggle with his mouth opening and closing rapidly when I was watching him today.

So are you thinking columnaris?

Should I remove the fish from the tank?

Personally I want to remove the fish and euthanise him or her. I do not want to lose the whole tank because of one fish. I also don't weant to treat the whole tank with antibiotics because I've done that before and caused "more than mini cycle". Nothing but more headaches and stressed fish and money for medication.

Serpae's were some of my first fish and I believe I picked some bad stock from petsmart. One of many lessons I have learned over the past 1+year.

Its always best to issolate sick fish to a hospital tank tnen treat the sick fish there.
Then just do some water changes on the main tank.
Hows he looking tonight.

The fish is acting 100% normal. The fish is white from his mouth to just in back of his eyes. His mouth still looks fine. Still no other fish have symptoms.

I can't move the fish to the hospital tank becuase the baby krib (current resident) is not big enough to survive in my other tanks.

I have maracyn and maracyn 2 ready to use.

Maybe I'll give it a good gravel vac and make sure the filter is clean tonight.

I would add the maracy one and two.
Columnaris can affect the whole head region rotting it away.
Don't forget to increase aeration as meds reduce 02 in the water.
Good luck.

I have trouble in my other tank now too. I think it may be related to a power outage we had a few weeks ago. My filters were off for an unknown amount of time. I never deteced any ammonia or nitrite but who knows. something has to have caused trouble in both of my tanks. Nothing else has chnaged in my system.

Before I add the medication I have a question. Will it affect my nitrogen cycle?

Depends on which med you add.
Maracyn one and two will knock water stats abit.
Antibiotics will wipe out the benefical bacteria colony out in your filter.
I would go in with maracyn one and two.