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Assistance with dead fish diagnosis . . .

Wookii

Member
Joined
13 Nov 2019
Messages
4,283
Location
Nottingham
Sadly I lost one of my Kubotai Rasbora last night - he/she was swimming oddly, in circles, not eating and eventually dropped onto a plant.

Unfortunately I had to do the humane thing at put it out if it’s obvious discomfort.

With such a small fish I’m finding it difficult to diagnose the cause of the ailment, so I’m hoping those more experienced can assist.

The fish basically had a small white patch on its left flank just below the gill. It looks almost like physical damage, but could also be fungal. Pictures were difficult to take in tank so I rested it in a sieve:

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C906EAF5-6834-49A6-89F8-C30913F9D8A6.jpeg


491FC099-A1D0-4C13-A1F5-A992C7C4AFAD.jpeg


My main concern is of course that this is nothing epidemic.

All the other fish seem fine, and I didn’t spot any issue with this fish on previous evenings.

I have discounted (perhaps wrongly) that this might be a parasite, as the tank has been treated for parasitic worms a few months ago with both Fluke Solve and eSHa-ndx.

The Kubotai’s can be pretty boisterous with one another, but I wouldn’t have thought they could inflict this much physical damage?
 
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Try photos on a neutral background - white usually gets my vote
Isolating fish to a “photography” tank often produces best photos
Also once fish is euthanized, try various angles, macro etc shots
If you’ve the interest, gently lifting gills to examine tissue (anaesthetized is best, as changes often occur with euthanasia/death) can be helpful
Without at least a dissecting scope, all of this is just a gross exam (various microscopic tissue examinations etc are needed to get any sort of real diagnosis)

The intank photo is actually quite good - as you can see the swelling along that side, also the white patchy stuff (more often bacterial rather than a true fungus)

The white patch on the opposite fin is also significant (fish’s health is suffering re these sorts of fin abrasions usually heal very quickly, persistence may indicate internal issues)

The rapid (was it rapid?) spinning about is more often linked to viral infections (though in reality, sick fish have a host of issues, with primary, secondary etc infections quickly developing once the primary infection begins to overwhelm immune system), but this can also be a general symptom of loss of equilibrium/balance preceding death

With rainbowfish, Mycobacterium is always a consideration - best support is optimum water quality, care, varied diet etc

It’s quite possible, this began with physical trauma where there was considerable tissue damage, then secondary infection giving rise to the white fluff appearance (once fish is compromised, this can develop within 1-3 days), also body swelling

Without anything specific, daily minimum 50% water changes always gets my vote, do this for several days
Depending on other livestock, plants etc, adjust water parameters to best suit the rainbows - how do present conditions compare to natural waters?
 
Try photos on a neutral background - white usually gets my vote
Isolating fish to a “photography” tank often produces best photos
Also once fish is euthanized, try various angles, macro etc shots
If you’ve the interest, gently lifting gills to examine tissue (anaesthetized is best, as changes often occur with euthanasia/death) can be helpful
Without at least a dissecting scope, all of this is just a gross exam (various microscopic tissue examinations etc are needed to get any sort of real diagnosis)

The intank photo is actually quite good - as you can see the swelling along that side, also the white patchy stuff (more often bacterial rather than a true fungus)

The white patch on the opposite fin is also significant (fish’s health is suffering re these sorts of fin abrasions usually heal very quickly, persistence may indicate internal issues)

The rapid (was it rapid?) spinning about is more often linked to viral infections (though in reality, sick fish have a host of issues, with primary, secondary etc infections quickly developing once the primary infection begins to overwhelm immune system), but this can also be a general symptom of loss of equilibrium/balance preceding death

With rainbowfish, Mycobacterium is always a consideration - best support is optimum water quality, care, varied diet etc

It’s quite possible, this began with physical trauma where there was considerable tissue damage, then secondary infection giving rise to the white fluff appearance (once fish is compromised, this can develop within 1-3 days), also body swelling

Without anything specific, daily minimum 50% water changes always gets my vote, do this for several days
Depending on other livestock, plants etc, adjust water parameters to best suit the rainbows - how do present conditions compare to natural waters?

Thanks Alto, its a Rasbora, not a Rainbow though.

The tank has 25% daily water changes as standard, the water quality is pretty much tip top as far as I'm aware, and its all from from RO - in tank TDS holds almost constant at 180ppm. It's probably not 'perfect' for the Rasbora as technically a softwater species, and my Seiryu stone prevents the water staying very soft, but pH, temperature and GH are all within the ranges Seriously Fish state.

The spinning was relatively slow, and perhaps more a result of the adjacent pectroal fin function near the damaged patch.

As I say, the rest of the shoal is in fine fettle, and has been since I got them last year. I hoping this is an isolated incident, but I wanted to try an rule out anything that might require tank wide treatment.
 
Hi Gareth (@Wookii),

It's always the most difficult part of the hobby, in my experience. Even with excellent books like A-Z of Tropical Fish Diseases and Health Problems (Burgess, Bailey and Exell), it's still daunting when trying to accurately diagnose what has caused the demise of fish. Sometimes, I resort to emailing Dr Fiona Macdonald, a fish vet. Her website is :


Good luck.

JPC
 
25% daily water changes as standard, the water quality is pretty much tip top as far as I'm aware
Microdevario kubotai are not the easiest fish to keep longterm, and they can deteriorate fairly quickly (though I’m not entirely convinced that this fish was perfectly fine the evening before - are you sure this fish has not been hiding in various places ... easy for such a small fish)

I’d have some eSha exit, ndx and Sera Baktopur on hand for treatments just in case
If fish are fine with larger water changes, I’d do 50% daily for the next 3-5 days, even if all remaining fish seem fine
(of course this is relatively easy I get to just Python and tap refill) but very clean water is always helpful whenever sick fish are present or have just been present ... lots of wonderful “cooties” jump ship as the host fish approaches death, others remain with the corpse as they’re playing the post death consumption card
 
The Kubotai’s can be pretty boisterous with one another, but I wouldn’t have thought they could inflict this much physical damage?
Not that I’ve ever observed in my groups
Which tank are they in?
 
Not that I’ve ever observed in my groups
Which tank are they in?

They are in my Kinabalu tank: Kinabalu (60 x 40 x 40)

I’m probably over egging the boisterous comment a bit, as my reference point is fish that show no observable aggression at all. The Kubotai occasionally chase one another, not far, maybe a few inches across the tank, like they’re establishing a hierarchy. As I say, I can’t imagine any of this resulting in physical damage.
 
Microdevario kubotai are not the easiest fish to keep longterm, and they can deteriorate fairly quickly (though I’m not entirely convinced that this fish was perfectly fine the evening before - are you sure this fish has not been hiding in various places ... easy for such a small fish)

Valid point, it could well have been out of sight for a couple of days I suppose. But had it been swimming oddly in sight on those days I would have noticed. I generally spend half an hour watching the tank every evening when I feed, as I’m generally feeding live food a pipette full at a time.

I have only had the fish 5 months, but I’ve had no issues with them so far other than this.

I’d have some eSha exit, ndx and Sera Baktopur on hand for treatments just in case
If fish are fine with larger water changes, I’d do 50% daily for the next 3-5 days, even if all remaining fish seem fine
(of course this is relatively easy I get to just Python and tap refill) but very clean water is always helpful whenever sick fish are present or have just been present ... lots of wonderful “cooties” jump ship as the host fish approaches death, others remain with the corpse as they’re playing the post death consumption card

I’m using RO, so the 50% water changes aren’t quite so easy, but I could double up the auto 25% changes for a bit.
 
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