How to explain mysterious deaths?

[dmaccy]

All

I would like some thoughts on a challenge. I have over the last six months had a high mortality rate. There appears to be nothing acutely wrong with the tank and water parameters are consistent (ammonia =0; nitrate= between 0 and 2.5; nitrite = 0; pH=6.2; carbonate hardness = 1dkh; hardness = 6dh/107mg/lCACO3). For info the carbonate hardness and pH did both used to drop, but I have since put some limestone in and it now stays stable.

Current stock is: 3x january tetra, 8x x ray tetra; 2x emperor tetra; 13x strawberry rasbora; 8x black neon tetra; 2 x black Venezuelan cory; 8 x smudge spot cory; 5 x albino bronze cory; 2 x red honey gourami

Over the last 6 months deceased fish include: 1x emperor tetra; 4x skunk cory; 1x flame tetra; 5 x January tetra; 1x albino cory; 1 x black Venezuelan cory.

There has never been any evidence of infections and deaths are rarely close enough together to indicate obvious infection. there is also no noticeable odd behavior

Tank Ciano Emotions Pro 120 (~240litres) running the internal filter which came with the tank and a Tetra ex 600 as well as a single air stone.

Applying Occam's Razor the only solution I am left with is that the male honey gourami is taking out other fish overnight, despite showing little aggression during daylight and only towards the female.

Fire away

 

[Byron]

How often and what volume are partial water changes? What conditioner do you use, and are you careful not to overdose? Are there any other additives (plant ferts, water additives, etc) used and which/how much?

Do you see any abnormality in the fish that die?

Do you have live plants?

While waiting on that info...if you even faintly suspect possible aggression (not suggesting this) it may help to sit without movement for up to an hour in front of the tank. After a while the fish "forget" you are there (your presence signals food, so any sign of you may cause totally different behaviours) and that is when you can see interactions better.

 

[dmaccy]

15-30% weekly, water treated with either tetra aquasafe or aquarians product.

Only other addition is the easy life root sticks which sit under the sandy gravel. And yes live plants.

 

[Byron]

I don't see anything here. Other members may spot something I'm not. What do you feed them?

 

[GaryE]

How soon after purchase have the deaths come?

It's a head scratcher.

 

[Back in the fold]

There is a thing called bad luck. There is also a real thing called Sudden Unexplained Fish Death. Many fish deaths can be explained and prevented and many cannot. How you know is anybody's guess. It always baffles me.

 

[Uberhoust]

I have to respond to anyone that calls on Occam's Razor in the description. But I cannot see anything wrong. The only thing I can think of is the honey gourami, but I don't have any personal experience with them.

 

[GaryE]

There are two fish sold as a honey gourami. One is the small, peaceful T. chuna that had the name for decades. The other is a larger fish that I think may be a hybrid based on T labiosa, and that would have the potential to be rougher. I wouldn't expect it to kill, but I have never kept that one.
The real honey gourami is a lovely fish that wouldn't hurt any other fish, but that may be why the trade name was hijacked. Good marketing via identity theft.

 

[dmaccy]

See attached photo of ¿honey gourami? (In question marks deliberately given the comment above.


It has had an ulcer on its side for over a year which I wrote off as genetics after trying numerous over the counter treatments (Uk).

Her insides now appear to be falling out.

Is this some sort of gourami virus (iridovirus? )? And could this cause other fish deaths?

On an unrelated note any recommendations for treatment of the gourami?

 

[Naughts]

Is this some sort of gourami virus (iridovirus? )? And could this cause other fish deaths?

Probably. The photo is not showing...

 

[dmaccy]

 

[dmaccy]

 

[Naughts]

Ouch
Do you have it separated?

 

[dmaccy]

I did twelve months ago when it first appeared, but as it wasn't healing and didn't seem to be causing any acute issues in other fish she is back in the main tank. I think I've three options?



EuthaniZe
Leave where she is and let nature take its course (which could be months?)
Put her in quarantine and let nature take its course (which could be months and my quarantine tank is only 12l).

 

[Slaphppy7]

That gourami is in bad shape, though I do not know what affliction it may be, nor if it is contagious

I believe I would euthanize, sorry to say