1 Platy Dead, 3 Sick, No Apparent Reason

[rhostog]

Day before yesterday I noticed one of the adult platys wasn't its normal self, but was hiding at the bottom of the tank. I fed them some squished peas, in case it was constipated, and it didn't get better or worse. Yesterday evening, I found a juvenile platy dead. This morning, the original sick one is worse, and now another adult and a second juvenile are also hiding. All 3 will swim if disturbed, but don't look normal, and quickly return to a hiding place and just sit there - not normal behaviour for them.

All the other fish appear fine.

I inspected the dead fish really carefullly, and there were no marks, no white patches, only a dark patch at its anus (which may have been there before). It maybe looked a little bloated but had possibly been dead all day. The sick fish also show no marks, definitely no signs of bloating.

Since first symptoms, I have done a water change in case that helps, but unless I'm sure it's necessary I don't want to do large changes as our tap water is high in nitrates (25-40) and also contains nitrite (0.1 - 0.2). (The filter and plants in the tank keep the tank water better.) I have also replaced the filter wool with a carbon filter in case something got into the water.

The only thing different recently was when I did a water change 2 days before the first sick fish, the spray bar was a bit blocked and I cleaned it out more thoroughly than usual.

Advice would be greatly appreciated. Thanks.

Tank size: 70 litre
pH: 7.8
ammonia: 0
nitrite: 0
nitrate: 8 ppm
Hard water
tank temp: 25.5 C
Running about 18 months.

Fish Symptoms: 1 juvenile platy dead, 2 adult platys & 1 juvenile hiding at bottom of tank, rest seem fine
Volume and Frequency of water changes: 12% weekly
Chemical Additives or Media in your tank: Water conditioner, liq plant fert. - same brands and quantities I always use.
Tank inhabitants: 4 zebra danios, 5 corys, 2 'black otos', 4 platys + 6 juveniles
Recent additions to your tank (living or decoration): 4 small (5-8 mm) Malaysian trumpet snails added approx 2-3 weeks ago from the shrimp tank where they've been breeding.
Exposure to chemicals: None known

 

[rhostog]

The two adult platys are still poorly. One is eating, but spending the rest of its time under a log. The other isn't eating but hangs at the back near the surface. The poorly juvenile isn't as bad - it's eating but hiding the rest of the time. The other fish all seem fine. There are no visible signs on the sick fish - some loss of colour just like if they're stressed, but no marks, bloating, etc.

If it's an infection, would the others be showing signs by now? If it's something got into the tank, wouldn't it affect the others? Unless perhaps it was something dropped in that these ate and the others didn't? I'm clutching at straws here...

Please help?

 

[WILDER]

Any signs of flicking and rubbing, excess mucas, darting, erratic swimming, laboured breathing.
Do any fish act listless and lethagic.
Can the fish maintain there balance in the water.
Do the fish look bloated or skinny.
Check the anus to see if its enlarged or red and inflamed.
Any fish have sunken in belly.
Any fish have bent spines.
What does it look like when the fish go to the toilet.

 

[rhostog]

Thanks for replying - I really appreciate your support.

No flicking or rubbing, so sign of mucus, not darting. The adults' breathing looks laboured - if they were mammals I'd say they were panting.

One sick fish is under a log, lying slightly on one side, and I keep thinking it's dead, but then if disturbed, it swims reasonably normally, and is eating a bit. The other adult hangs near the surface at the back of the tank and isn't eating (was eating 2 days ago). The juvenile seems better this afternoon, just less active than normal - I wouldn't worry about him if it wasn't for the other two.

Both adults definitely very very listless and lethargic.

When they swim, they're not tilting, but they are slow and like it's a real effort. One adult seems to be holding its head upwards. The one that's under the log is lying partly on its side, but straightens up when it swims.

Not skinny, not bloated. They were quite tubby to start with.
The anus isn't red or different to normal, except there's a small pale blob by the sickest fish's anus. It looks like a bit of pale poo, not like worms or anything. Nothing on the others.
No sunken belly. No bent spines. No visible marks. Gills normal colour. Both adults pale as if stressed.
I've been watching them but not seen them go to the toilet. I will keep watching.

Thanks again Wilder for replying - it's useful to have suggestions what to look for and any ideas you have would be very gratefully received. Or even just the reassurance that I'm not missing something obvious.

 

[WILDER]

Teh fish that are ill might be to far gone to save.
But I would still add anti internal bacteria med by interpet to the tank.

Keep a look out for internal parasite signs.


The third type of infection produced by Aeromonas is by no means the least. This form is often the most virulent (potent) and can be rapidly fatal. This insidious form does not produce any noticeable external ulcers. The most notable feature is a behavioral change in which the infected fish generally become listless and lethargic. Some fish may lose color or appear darker. The fish do not feed, frequently seem off balance and may sink to the bottom laying on their sides. The course of the disease is rapid, and by the time the behavioral changes are noticed, the entire population of a tank may succumb, sometimes in a day or so. This is an internal infection, with the bacteria being found in the kidneys and blood of these fish. The bacteria produce potent toxins that account for the severity of the disease.

 

[rhostog]

Oh dear, that sounds like the symptoms. I'm not sure though... the sick fish started showing symptoms on Saturday and it's Tuesday now, and I've only lost one fish (so far) - seems like this Aeromonas would have caused greater devastation by now? The juvenile I was worried about earlier seems a little better this evening, and one of the sick adults continues to eat, even though it's spending the rest of its time under a log and is swimming with its head up almost vertical. I doubt the worst adult will make it through the night, but I'm surprised that the rest all seem unaffected.

I'll get some anti-bacs tomorrow but I'm reluctant to use if I'm not sure that's the cause... I'll see how they are when I get back from the shop and make a decision then.

I've been checking for any visible marks, and trying to spot the sick fish going to the toilet (without success so far) - is there anything else I should be doing to look out for signs of parasites?

I'm still wondering if it's possible it's some kind of poisoning? That perhaps they've eaten something that found its way into the tank when I was cleaning it? Just trying to account for why it hasn't spread through the tank (yet)...

Thank you again for your support and advice.

 

[rhostog]

I couldn't get Interpret Anti-bac from the nearest shop, but can get to 2 different shops later today so hope one of them has it. If I can't get Interpret, is there another brand you would recommend?

The 2 sick adult fish are still alive! and no better or worse. One spends its time pretending to be dead under the log, but is eating - it swims with its head up like its tail is really heavy. The other spends its time hanging near the surface at the back of the tank, but I think it ate a little this morning. I think the juvenile is OK, but not sure, it's maybe a little lethargic but I might just be paranoid. All other fish still OK.

Thanks again.

 

[WILDER]

A sign of swim bladder is when the fish tail looks like it's weighing them down in the water.
What do you feed your fish.
I would still try and get the anti internal bacteria med by interpet.

if a toxin was in the tank the fish would show these signs.
Gasping or laboured breathing, excess mucas, darting, erratic swimming, turn upside down.