Tiger Barb turning black and not feeling well

[Beach Barbie]

About 2 weeks ago, one of my Tiger Barbs started changing color, darkening to the point that most of the body looks black. It was struggling to swim correctly and wasn't eating. None of the other fish seemed affected. when I took these pictures, I noticed that the tail is looking very scraggly.
I put the fish in its own tank with a bubbler. The water is 60% from the big tank and 40% fresh.
I just treated with the antifungal API Pimafix, active ingredient: 1% Pimenta racemosa. It should also treat for internal bacterial infections.
Is it a fungal problem or something else?
Big tank:
75 gallon
Has been running for about 3 years
70% water change every one to two weeks
Filter: Tetra Whisper EX 70
Ammonia: within safe range, but has gotten high on occasion. Last time I checked about 2 weeks ago, it was in the "stress" range.
pH: 7.2 (I have been trying to lower the pH, but I still need to be more diligent at keeping it lower)
Animals
2 snails (have been present for 6 months)
3 Placo (1 has always been in the tank, two were introduced from my pond 6 weeks ago)
5 Tiger Barb (have been present for 2 years)
2 Platy (have been present for 4 years. I did buy four about 10 weeks ago and several died)
2 Black Skirt
2 Longfin Black Skirt
Plants
Lucky Bamboo (Dracenea)
Subtrate
Gravel and shells.

Tank with sick Barb
10 gal
Bubbler, no filter. I don't have a small enough filter for this tank.
pH 7.2
Ammonia is in safe range

Thanks for your help!
Barb

 

[lauraf]

Hi Barbie. If you are showing any ammonia at all you have a problem. That could very well be what has affected the tiger barb. I wonder if the two new plecos you introduced have upset your bacterial cycle. They can be huge waste producers. If you have any ammonia, you need to do large water changes, daily if necessary, to keep the ammonia as close to 0 as possible.

 

[Beach Barbie]

Gotcha. I will do water changes as you suggested. I didn't realize that placos produced a lot of ammonia. I knew they pooped a lot.
I have noticed in other peoples threads, they mention an actual ammonia level. My test kits only say Fine, Stress, Danger, etc., when it comes to the levels. Are there tests that will give a numerical level?
Barb

 

[KcMopar]

Yes, API make a good test kit or a complete kit package as well. No amount of ammonia is OK. Thats like saying will its only a little poison so it will be fine to ingest. The API is a liquid test tube kit that is pretty accurate for the money and considered so by the majority of the fish community.

 

[Beach Barbie]

Yes, API make a good test kit or a complete kit package as well. No amount of ammonia is OK. Thats like saying will its only a little poison so it will be fine to ingest. The API is a liquid test tube kit that is pretty accurate for the money and considered so by the majority of the fish community.

Excellent point about ammonia levels. *twirlysmi
I'll get the API kit.
My Tiger Barb and I say thanks!
Barb

 

[Beach Barbie]

So! I did as y'all suggested - frequent water changes and keeping a closer eye on the ammonia levels. After finally getting a hold on the levels in the big tank, I was able to put the sick fish back in that tank. He/she still isn't completely better, but is much happier with his tank mates. He's trying to feed, but still having trouble swimming.
Thank y'all! I'm now a much better fish Mom. *SUNSMILE*
Barb

 

[lauraf]

That's great to hear, Barbie!
Cheers,
Laura