my guppies die with rotten fish tails and scoliosis

[rainbow66]

Everything was fine until I went away for 15 days last year. I used an automatic fish feeder which I think worked fine. just Before my trip, I changed the water. And I had added a new guppy before my trip.

After my return, every week or 15 days, I have lost one or two guppies. As it is seen in the pictures, they have certainly have rotten fish tails and scoliosis before they die. scoliosis is not because of breeding and fighting and it’s not hereditary. They come together and fish die.
My aquarium is 120 liters and contain(ed) 50 guppies. Like I said everything was fine for a long time until my trip and before adding the new guppy. They lived together fine and with almost no deaths. I cared well now and then.
It has been 9 months and I couldn't find a solution for this problem. I regularly change water. I feed them with quality food. I tried some antibiotic and other medicine (not in the main tank) with no effect. When I see a fish with a problem, I take it to another tank.
I am almost tired now and afraid to look at the tank. Can anyone understand what’s happening and advice me something?

 

[rainbow66]

no answers?

 

[NicePoeci]

So you believe that the bending of the spine occurred in a 2 week period? With the information I have and looking at the complete clarity of your water and the fin rot I have to assume you are keeping them in very soft and acidic water. Females especially because of the breadth of reproduction require tons of calcium and other trace minerals in the water to help produce skeletal symmetry etc. I keep almost 30 aquariums with guppies and endlers and quite often some tank have green water and they love it. I use RO water so I remineralize the water and yes, the entire species really loves hard nutrient dense water. Its neccessary for their reproduction. SO IM not sure thats your problem here at all, buutt, from the looks of it they are not being kept in the water they have evolved to need. Warm, Hard and definitely above above 7.0 ph.

 

[NicePoeci]

For the fin rot I would buy some of that stress coat. Its basically aloe vera and their slime coat is literally their immune system.

 

[NicePoeci]

If you read this and suspect this Could be the issue I recommend buying a GH booster and Trace Minerals for Freshwater Aquariums. I use many many minerals in my water but msot important is Aquarium Salt, GH Booster of some sort and Trace Minerals for the species.

 

[NicePoeci]

Also check nitrates, nitrite and ammonia levels that could be causing the fins to melt/rot etc.

 

[rainbow66]

thanks for the information. I will buy some test kit and see what's going on. thanks again.