White "thing" on mouth of Harlequin Rasboras

  • #1
1. Size of tank? Originally in a 36g community tank. Now in 10 gallon QT tank

2. Water parameters
a. Ammonia? 0
b. Nitrite? 0
c. Nitrate? 0
d. pH, KH and GH?
e. Test kit? API Liquid Test Kit

3. Temperature? 78*

4. Freshwater (fresh water) or BW (brackish)? Freshwater (Freshwater)

5. How long the aquarium has been set up? 36 gallon has been about 2 months... 10 gallon QT has been recently set up.

6. What fish do you have? How many are in your tank? How big are they? How long have you had them?
10g QT tank only has these 7 Harlequin Rasboras

7. Were the fish placed under quarantine period (minus the first batch from the point wherein the tank is ready to accommodate the inhabitants)?

8. a. Any live plants? Fake plants? QT tank has no plants
b. Sand, gravel, barebottom? QT tank is barebottom
c. Rocks, woods, fancy decors? Any hollow decors? QT tank has some decor

9. a. Filtration? HOB for 10 gallon
b. Heater? 25 watt heater

10. a. Lighting schedule? What lights are used? Just natural sunlight
b. Any sunlight exposure? How long?

11. a. Water change schedule? Daily
b. Volume of water changed? 50%
c. Well water, tap water, RO water? Tap Water
d. Water conditioner used? Prime
e. Frequency of gravel/sand (if any) vacuumed? N/A

12. Foods? New Life Spectrum 1mm pellets
How often are they fed? Once a day

13. a. Any abnormal signs/symptoms? No, just physical
b. Appearance of poop? Normal
c. Appearance of gills? Normal

14. a. Have you treated your fish ahead of diagnosis? No, just water change.
b. What meds were used? None.

I've noticed this white "thing" on one of the mouths of my Harlequin Rasboras about 3 weeks ago. I didn't think too much about it at the time.

Last week, I noticed that a second Harlequin Rasbora also had this white "thing" on his mouth. While I was wrangling all 7 out of my 36 gallon tank, and finally got all 7 into the QT tank, none of them had that white "thing" on their mouths, as if it all rubbed off.

I'm doing a 50% water change every day.

Currently at day 6 of QT, the two had white "thing" reappear.

Any suggestions?

What is this white thing?

They are all eating well, so it's just a physical "thing" that doesn't seem to affect them at all.

  • #2
It could be cotton mouth but that would make them loose appetite so I don't know.
  • Thread Starter
  • #3
I'm not to sure if it's cotton mouth. From what I've read about cotton mouth, it's highly contagious, and very deadly if not treated in a timely manner.

It's been about 3 weeks since I've noticed it, and this last week all 7 Harlequin Rasboras were put into a QT tank, with no treatment, other then changing the water... and the original 2 has it, but it hasn't spread to the other 5.

They also say, that the fins would also disintegrate, which hasn't happened after all this time, and it hasn't spread.
  • #4
If it's been going on that long and the fish are still alive and acting healthy, then I'd say some sort of fungus. Columnaris has a cottony growth on the mouth, but the fish don't live long. One of my BoesmanI rainbows had a persistent cottony growth on his mouth which seemed to come and go. I started using Kordon NovAqua+ and Kordon Fish Protector with water changes and the white stuff went away. That was almost a year ago, and this fish is thriving.

I'm concerned about the 10 gallon not being cycled. Can you transfer some cycled filter media from your big tank to the 10g's filter? The stress of going through a cycle will not help your fish. Good luck.

Edit: The Kordon products contain vitamins and echinacea (an herb which boosts the immune system).
  • #5
I just went through something similar with my new harequins. Thou with mine I am pretty sure they had columnaris or something very similar because one would get a spot on its mouth or side and within the day would be dead. Lost one a day for four days. I treated them with pimafix and melafix for 2 weeks and no others have gotten sick. Thank to a Q-tank no other tanks were infected.

I also discovered something-When I first got them I fed them pellets-like all my other tanks. It seemed like the weaker fish would eat the pellets and I don't know scratch it mouth and would get a white spot and be sick very soon after-they were fed pellets the first 4 days and one weak fish died each day. Switched them to flake food and haven't had any die. Is that coincidence or is there a link? I don't know but they will get flakes for the rest of their fishy days.
Hope you solve your mystery.
  • #6
This sounds exactly like what happened to my harlequins. Out of no where a white bump appeared on the mouth of one fish. It hasnt spread or anything and the fish is swimming actively and eating like a pig. My guess would be that it injured itself in your case and mine. If it did injure itself, clean water should heal him in a timely manner.

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