Please help!

[Booby]

I wonder if I can get a little advise?
I have a 227 litre tank. I have 3 fantail fish and 8 small minow type fish. I did have 3 golden loaches that were around 2 years old. I've never had any issue until recently all 3 loaches got dropsy and unfortunately none survived. Obviously I cleaned the tank and have kept my eye on the other fish. 2 of my fantails have red streaks in their tails. At first I thought this was amonia poisoning so I did regular water changes. I've tested as all my levels
Amonia 0
Nitrite 0
Nitrate under 20
My waters is fine although my fish aren't getting better. Could there be another explanation?

Hopefully I haven't missed anything

 

[Roz]

What is the water temp?

What is the pH?

I have read that goldfish really should be kept with goldfish.



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[Booby]

Thank you for your reply.

The water temp is around 22C and the PH was 7.0 at last reading.

All the fish have lived quite happily together for a couple of years.

Nothing has changed in the tank or in the surroundings which is why I can't figure out what's wrong with them.

We've had hot weather here at the moment but as I've had the fantails a number of years I didn't think it would affect them now.