My discus are dying they are only youngsters and came from a very experienced breeder.

In my 240ltr tank i have 5 angels, 6 corys and 3 Discus (3 have died in a fortnight) until today my water has always been spot on 27-28 degrees, nitrites 0, ammonia 0, nitrates 5

I am keeping all the fish in exactly the same conditions as the breeder, he has kept all fish in the same tank. In fact he has adult fish and many many more than i have right now.

We are buying RO water for our tank, we are using tapsafe.

All the other fish in my tank are perfectly healthy. Just my discus

Why are you using tapsafe with RO water?
Everything tapsafe protects against has been removed by RO.
What are you adding to the RO water before you use it?

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Dont generally add anything to the water since we were advised we didnt need to by the guy we buy the RO from apart from Tapsafe.

We were using tap water treated with tapsafe but because our water board did something to the water pipes the quality has been disgusting.

Ro water is stripped of every impurity but I believe that means your going to need to add stuff back into it to make it suitable for your fish. Tap safe will have absolutely NO benefit. I would be very hesitant to take this guys advise if he didn't even know this.

Ro water is not suitable to keep anything in untill it has been remineralised.

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Ok so strip this back for me because I am getting into a tither...

What do i need to add to RO water for it to be safe for my fish?

Would it be more beneficial to go back to the tap water?

All my other fish seem absolutely fine. We had some Angels the size of 5pence pieces and they are almost 50pence size now.

My plants have doubled in size.

My tank has 2 very decent sized pieces of bog wood.

My tank was second hand and transported to us 30 minutes after it was emptied. It has an undergravel filter and an external filter. The water has always been spot on.

We do a 10% water change every 2 days and on a sunday we do a 20%change and general tank maintence.

As i am typing this another discus looks like it will not be with me in the morning. I am so upset its unreal.

I understand that you may have placed your faith in the advice given to you by the breeder, but you really should have done your own research before buying the Discus. They are a finicky species and don't react too well to small mistakes.

As mentioned above, Reverse Osmosis is a process that removes about 99.9% of every impurity, mineral and element from the water that passes through the RO unit - leaving roughly 99.9% pure H2O with very little dissolved oxygen, no minerals or carbonate hardness and a very low pH. If it's used in its 'neat' state, fish will be sent into a condition known as osmostic shock, which usually results in death.

You need to re-mineralize and re-oxygenate the product RO water before using it. When I used to keep Dart Frogs I would use Tropic Marin Re-Mineral Tropic powder and mix the water using a submersible pump to bring back oxygen and stabilize the pH at around 6.5-6.8.

Keep an eye on the water quality, and if in doubt, re-test using a different test kit. New Discus often hide-away, turn dark in colour and refuse to feed. They are also often affected by internal parasites which can cause an entire list of problems.

I did my research, was happily using tap water with my conditioner for 2 months. Then suddenly the water company did something to the pipes in my area and since then my tank hasnt been the same.
Before buying any species i do hours and hours of research and have never bought any pet on a whim.

I have tested my tank and so has breeder and pets at home and its excellent and always has been.

Im going to start doing 30% water changes.

Oh and i have dewormed my discus when they needed it. My breeder gave me Kusuri Wormer Plus for them when the fish started th get unwell because of their white poop.

Think this is just a case of me going back to step one and looking at everything.

My breeder was out of contact for a couple of days due to a severe power cut his end, i never usually go for advice anywhere else but went into panic mode because he wasnt available. It was a local fish shop that gave us the bad advice regarding RO. Its 6am here and i sent him a message already regarding what has been happening and thankfully he is coming over to check our tank and water quality himself.

Thank you for the advice.

Typical of aquatic stores, they give out false info so they can try to sell you something you don't need!

I'd buy from a breeder any day, given how shocking the advice is from a growing number of aquatic stores I've visited in the UK. Ironically, the best aquatic store that I've ever visited happens to be Vivid Aquariums in Canoga Park, California.

By the way, are you using activated carbon?

Nope was advised that activated carbon should be used only when your treating your fish for something then remove it.

Im going to do 20% daily water changes.

We also went back to feeding te fish frozen bloodworm from the place we always buy it from the Pets at Home apparently had added vitamins in it which now i think about it was the day before the latest fish got sick and died. The fish also didnt dive in they they usually do when we feed them their blood worm. Which is every other day. They go crazy for it.

We have gone back to every event that has happened before, during and after the last fish died.

I went to bed last night at midnight then woke up at 5am because i was so anxious about the tank.

I will do what it takes to get my fish on track and healthy. I just feel stumped atm.