Sinking, Clamped Tails and Recent Deaths

Hi everyone,

I’m brand new to the forum and a brand new owner of CPDs.
We recently got 8 juvenile CPDs, and around a week or so later (after they seemed to be doing well) we added a further 6 juveniles CPDs.
All of the fish, with the exception of 1, seemed to be healthy – there colour turning nice and dark with vibrant orange tails. The 1 exception was a female who’s tail appeared to be sinking and she was struggling to swim.

We went away for the night about a week later and came back to find 2 dead, 1 completely unaccounted for and the other 11 had lost all of their colour and energy and their tails were sinking and they were struggling to swim. Some of their tails were also clamped. A couple also have swollen bellies. We have since lost 2 more and we have no idea what’s gone wrong. (strangely enough the 1 female that had the sinking tail from the beginning is still alive)

The water parametres are fine. We did a water change and left the light on overnight, this seems to have really helped as most of their colours are coming back – but 2 fish still look very unhealthy and very pale with sinking, clamped tails and swollen bellies. Swimming looks an effort for them too.

Its thankfully been 24 hours since we lost our last one (I’m touching wood whilst writing…..)

Has anyone experienced anything similar? Or does anyone have any advice?
We’d be grateful for any advice!

Thanks everyone.