# Cory Red Blotch Disease



## Plexus

Hopefully someone can help

Whilst doing my daily routine of checking the tanks, I have noticed that one of the Cory Catfish has what looks to be red blotch disease. All other inhabitants of the tank look to be just fine, including the other 4 corydoras. 

The only noticeable difference is a few plants have melted back a little. I did a water test to find that ammonia is pretty much 0, nitrates are a little higher at 20ppm (I water change every Sunday), but nitrites were at 0.25 (Usually 0 of course)

I recently treated the tank with hydrogen peroxide to battle some BBA (this has worked well). I also raised the temp of the tank by 2 degree Celsius about a week ago. Has the treatment caused the increase in Nitrites, or this red blotch disease?

I have a 2nd tank that I can quarantine the wee fella in for now, is this condition contagious?, and what is the best treatment?


Thanks, Andy


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## alto

Hi Andy

not sure about what this fish is suffering from but he(?) looks rather ill - emaciated (body) condition suggests that whatever is going on, has been doing so for awhile, he also looks very depressed & those clamped & collapsed fins are often a sign of advanced illness ... once at this stage, recovery is not high probability  



Plexus said:


> I recently treated the tank with hydrogen peroxide to battle some BBA


Any chance that this fish received a concentrated dose of hydrogen peroxide? (eg swam through a cloud of peroxide just poured into the tank) or did you dilute the peroxide before adding to the tank?
(re possible chemical burns could produce this sort of condition) 




Plexus said:


> red blotch disease.


this is a fungal disease/condition so any "treatment" is just supportive care (ie there are no medications which treat the causative disease agent) - optimum water & foods & minimal stress.
I would remove this fish to a quarantine tank, especially in the interests of other fish in the tank re contagion, not just of possible fungus, but other pathogens that have proliferated on/within this fish as his immune system has weakened (ill fish have rapidly increasing levels of external & internal parasites/bacteria/virus etc)



> A pathogenic fungus, _Aphanomyces invadans_ causes EUS. Infection occurs when motile spores in the water are attracted to the skin of fish. The spores penetrate the skin and germinate, forming fungal filaments or hyphae. The hyphae invade widely into the surrounding skin and deeply into underlying muscle tissues, resulting in extensive ulceration and destruction of tissues. *Low water temperatures* depress the immune system of fish, which may partially explain the apparent dry season occurrence of EUS. There appears to be no definite relationship between dissolved oxygen levels and EUS; affected fish have been seen in water with *dissolved oxygen levels* of between 2 to 8 ppm[1].
> 
> Previous outbreaks of red spot disease have been associated with acid water run-off, particularly after heavy rain following a prolonged a dry spell, as well as other factors such as prolonged cold temperatures, crowding, and conditions associated with drought.



I don't know why nitrites have appeared in your tank, it may be related to the peroxide treatment (you provided no details) or the BBA die off, or seasonal variation in your tap water ... I'd monitor the tank water quality daily, increase water change frequency (25% daily).


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## Plexus

Hi Alto,

Thanks for your advice.

I use 3% HP in a spray bottle. I siphon out some water to expose the effected areas, approximately 20% volume in a 240L tank. I then spray those areas and leave them for over an hour. I'll then top up the water level, followed by a 50% water change. The filter is not running whilst this is all taking place.

I literally tend to the tank every morning before I go to work, and this guy has been fine up until yesterday. He was swimming around happily the night before eating up bloodworms.

I'll quarantine the poor fella for now. I thought it might've been kinder let him go, but I'll see how he is over the weekend.


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## john dory

Probably crashed the filter with the hydrogen peroxide.


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## john dory

Looks like his mouth is damaged,due to the sharp gravel also.


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## alto

Poor fellow indeed - always easier to discuss euthanizing than actually carrying it out ... I tend to "ask" the fish, if he hasn't given up, I won't either
I try to make fish as comfortable as possible, then wait & see ...

I used to euthanize at an earlier stage (more clinical in my analysis) but there is a natural progression to end of life  which generally includes a state similar to "shock" wherein the individual is no longer consciously feeling the discomfort & they seem to just slip away without apparent signs of distress (unlike the primitive response to euthanizing chemicals - I watched a most horrifying fish experience with MS-222 (at the vet clinic), fish was terminal but not yet in a dissociative state ... yes, it was somewhat of an "adverse reaction" but there was no going back & no doubt that fish was in extreme distress

This article is worth reading - or you can get much more technical & read the actual veterinary reports (just avoid a lot of the forum balderdash)

http://m.wikihow.com/Humanely-Kill-a-Fish

If fish was basically "fine" the day previous, this is NOT EUS or red blotch disease, I'd guess the poor fellow somehow got peroxide burns - any chance he's been in hiding & recently reappeared in the tank? creating this (timeline) confusion


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## GHNelson

Hi
Could be a internal heater burn....if you have one without a plastic cover!
hoggie


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## sciencefiction

alto said:


> not sure about what this fish is suffering from but he(?) looks rather ill - emaciated (body) condition suggests that whatever is going on, has been doing so for awhile, he also looks very depressed & those clamped & collapsed fins are often a sign of advanced illness ... once at this stage, recovery is not high probability



Hey Plexus. I must agree with Alto. The fish seems to have been in that state for a while. Maybe it was hiding? Think about the last time you saw all corys together. Just by looking at the current state, its hard to say what caused it. One must know how it progressed. At this stage, I wouldn't be very hopeful, but if it were me, I'would try anyway.. If the fish is moved, it must be in a well cycled tank and keeping it pristine with daily water changes without stressing the fish.  Any bit of ammonia/nitrite will just kill it. The fish probably needs antibiotics, both for gram negative and gram positive to cover all fronts and these are not easy to get if you're in the UK.


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