A Fresh Start

[BalloonMolly]

I do use the hot tap, I'll try using cold + boiled instead.

Tap parameters are:
Ammonia, Nitrite - 0ppm
Nitrate - 20ppm
pH - 7.5. I leave water for changes overnight for CO2 to do its thing as the tank is at 8.2.
GH - 16 (same as tank)
KH - 18 (same as tank)

Tank has been cycled since end of November and the guppies/Endlers have been in there for a month.

Thanks for the tips, both. Fish suffering is never good, but it's even more frustrating when you aren't sure why...

[black ghost]

Could always be the fish themselves, especially if they’re a mass produced farmed variety. All farmed fish get weaker as the generations progress, and Endlers are much more popular now than they used to be.

[BalloonMolly]

I'm sure it's a factor. It's so sad to see them deteriorate like this. At least the male who was first affected is able to interact with the others more again, hopefully the other will follow suit soon enough

[Martinspuddle]

Can you post a picture of them.

[BalloonMolly]

Absolutely, will take some later

[fr499y]

and please use dechlorinator / water treatment.. leaving out for 24 hours isn't the best practice!!!

If you have Chloramine in your water then it'll still be there 24 hours later and that could be the cause.

Chlorine and chloramine are toxic to fish, other aquatic animals, reptiles and amphibians. Unlike humans and other household pets, these types of animals absorb water directly into the blood stream. Don’t keep these animals in water that contains these disinfectants. Unlike chlorine, chloramine cannot be removed by letting water sit out for a few days.

[Martinspuddle]

I leave water for changes overnight for CO2 to do its thing as the tank is at 8.2.

and please use dechlorinator / water treatment.. leaving out for 24 hours isn't the best practice!!!

If you have Chloramine in your water then it'll still be there 24 hours later and that could be the cause.

I didn't notice that, reading the OP's post. Think you might have hit the proverbial nail on the head and would explain the issues.

[BalloonMolly]

Sorry, should've clarified that I do use dechlorinator! I add it with the water, then leave so the pH stabilises.

[fr499y]

which one do you currently use?

[BalloonMolly]

Stress Coat or the Fluval AquaPlus. Couldn't find my old Seachem Prime but wonder if it's worth using for peace of mind over additional "nasties" in the water...