54L Tank - Update

Unfortunately I had a couple more cardinal tetra fatalities in late July, a week apart, as follows:
* One had looked larger and bloated (only when viewed from above during water changes) for a couple of weeks but nothing else seemed ontoward and I assumed it was simply a healthy appetite / female.  One evening, however, there was a very sudden demise (discolouring, panting and buoyancy awry) evolving into being sucked against the filter intake ten minutes later, and it was clear that I needed to "intervene" as the end was imminent and the others were intrigued.
* A week later, despite all remaining cardinals in perfect health, one was missing during one of the several-per-day headcounts - it was lying upside down in some java fern.
There's no obvious reason for their demise ie water quality or otherwise.

I'm now down to 4 cardinals, plus the 5 espeis.

I had convinced myself that the 54-litre tank should only house two species.  However, I'm not convinced that cardinals are the optimum choice for my tank (although in theory they ought to be).  Getting more espeis probably isn't wise as they are quite boisterous - one young male in particular - and any more might feel intimidating for the remaining cardinals.

However, ember tetras seem to me the perfect choice - and would appreciate the hygrophila guanensis that I've kept alive and been propagating for 2.5 years (touchwood).  I was thinking of a small shoal of 6 for now - increasing to the recommended 8-10 when capacity allows.

Thoughts welcome.   


 

I had the thought that the cardinals are probably dying natural deaths due to old age(?) An organ fails, and death can be sudden. Maybe the bloating was leakage...

I had cardinals in a 6x2x2 a few years ago. They ‘roamed’, stringing themselves out like a train as they slowly went from end to end, at the back a few inches above the sand. I can’t remember how many, but about 30 I think. That seems to be what they do. Their tankmates (lemons and glowlights) kept themselves together more and weren’t so bent on being on the move all the time. So maybe they need more space than we think.

I’ve never kept Embers but they seem very nice and placid.

Any further thoughts/updates @fcmf ?

Fair enough, I will say I’m certainly a fan of my ember tetras, they are peaceful yet outgoing. The bigger the group of them the better in my opinion

Sorry to hear this - I did write a piece somewhere on here a while back about my suspicions regarding genetic issues with cardinals which could be a factor here too.