# Help My Fish Are On a Killing Spree



## garofalo79 (Jan 25, 2012)

About 4 weeks ago, my 55g had 16 Demasoni, 4 albino snow whites, 4 rusties, 5 yellow labs, and 5 baby demasoni. Aside from the demasoni babies, all were roughly 1 year old. I introduced 2 yellow labs and the 4 albinos roughly 10 weeks. All water parameters were fine, I have a large canister filter, and the temp is roughly 78 degrees. I'm not religious water about water changes but I do stay on top of them fairly well.

Now 4 weeks later, I am down to 13 Demasoni, 2 Albinos, 3 Rusties, 2 yellow labs, and up to 6 baby demasoni. I have lost 9 fish over the past 2 weeks, sometimes up to 4 a week. My fish are on a killing spree! What can I do to calm this aggression????

I don't think the killing spree was caused by adding the albinos and the 2 yellow labs because the killing spree didn't start until 6 weeks after they were introduced. However, maybe it took time for the aggression to build up. My other thought is that since the baby demasoni have not only survived this killing spree but have actually increased by 1, that the parent deamsoni are killing the other adults as a method of protecting their fry. Also, the killing spree did tend to start after I moved the tank from one wall in the room to the opposite side and I did change the rock layout bit but I had been changing the rock layout every so often prior to this as well so maybe that was only a coincidence.

Any advice is greatly appreciated!! Thanks!


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## Fogelhund (Dec 3, 2002)

Have you witnessed fish getting picked on? What makes you believe it is a killing spree and not bloat?


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## dstuer (Mar 27, 2013)

16 demasoni and their fry in a 55 would seem to full capacity to me, but maybe because all had set up a mutual hierarchy, it worked.
But by adding new fish, the balance was turned upside down, creating enough stress to break the hierarchy down.
Were the new fish quarantined? It sometimes takes time for disease to present, and crowded conditions can bring out disease conditions that were nonexistent before.
Water parameters aren't the only limiting factor in aquaria, tank footprint/population can be much more important.


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## garofalo79 (Jan 25, 2012)

I do see the demasoni being aggressive to others. Also, I have seen injured fish- darkening scales and clipped fins. I haven't noticed any fish with a bloated appearance. But I'm not sure if darkening scales is a sign of bloat.


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## garofalo79 (Jan 25, 2012)

The new fish were not quarantined so maybe it is disease taking a bit of time to show itself. Is there any general treatment I can use as I am not sure if there is a specific disease diagnosed? I already add some Epsom salt and aquarium salt with each water change.


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## Fogelhund (Dec 3, 2002)

Do the fish that die go off on their own for a few days, or a day before they die?


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## garofalo79 (Jan 25, 2012)

Some have gone off on their own for a few days then died and some have seemed to die suddenly. The fish that do go off on their own typically look beat up when they do and die within a few days. That being said, I have 2 smaller demasoni that look slightly dark, some clipping, and have been off on their own for over a week now. They appear to be recovering but I am not positive.


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## Fogelhund (Dec 3, 2002)

My opinion is that the changes in the tank, lead to too many fish, or stress in the demasoni. Ps. demasoni seem to stress easier than other mbuna, and it often leads to bloat. While bloat itself isn't contagious, it does seem to strike multiple fishes at once when it does happen. I would think about treating for bloat and rethink the stocking. You were full at the demasoni and Labs.


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## Iggy Newcastle (May 15, 2012)

Have you noticed any fish spitting food or no longer feeding? Hiding during feeding? Any white/clear, threadlike feces? I've had fish come down with bloat, and suddenly become the target of others who were sub dominant of the infected fish. It was as if they sensed weakness. It sounds similar to what you're experiencing with fish who look banged up and isolated from the other fish.


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## garofalo79 (Jan 25, 2012)

The fish aren't spitting out their food but a few are a bit reluctant to eat during certain feedings but are usually eating normal by the next feeding or the one after. There has not been any white/clear feces. All the fish seem to be defecating quite a bit.


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## Floridagirl (Jan 10, 2008)

I agree with probable illness. Adding new fish creates stress, and can lead to disease, especially if fish are not quarantined first.


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