Slowly Losing Ricefish

[G Harnish]

Interested in any and all help-I have not been able to crack this on my own. Quite puzzled. 

Bottom line: I am slowly losing fish every week or so. Started in late Sep. Seems to begin with slight bloated appearance, worsens, swimming affected, sometimes extreme large belly and curved spine, and then death.  First one or two I was not concerned, but now a sustained pattern. 

Background, water, meds, and diet below.

Photos attached are Ricefish taken today showing bloat/early bloat (photo sof single fish) and normal Ricefish (shown w platy tankmates-no issues with Platys). 

I bred and raised several dozen blue sparkle Ricefish this summer in my outside tub. Fun! Around  early Aug moved about a dozen to indoor grow out tank along with wagtail Platys I am growing out. Goal was to finish grow out, make sure they were in great shape, then sell to LFS (my first sales). There have been no disease or death issues with Platys. 
 

Water and Tank: 77 degrees, pH 7.2, KH 40-60, GH  100/120, zero ammonia and nitrites, nitrates 20-40, weekly water changes, tank is not planted, run 1 TBS aquarium salt/10G, sponge filtration 

Diet: mix of live BBS, frozen BBS (homemade), Xtreme micro pellets (open 4 months but refrigerated), Xtreme krill flakes (same storage), Repashy S Green. Other tanks feed same foods w no issue, including the sibling Ricefish remaining in outdoor mini tub (no disease or losses apparent).

Meds: Two rounds coop trio when brought Platys and Ricefish together in this tank-starting early Aug. Then two rounds Xpel (later in Aug into Sep)  First deaths began roughly late Sep. 

Have just gone through a 5 day course of Paracleanse. And took the attached photos today with a couple more fish showing beginning visual symptoms that have led to previous deaths.  

[CJs Aquatics]

This is quite odd and unfortunate. I’m not the most well versed with disease but I’m almost wondering if it’s more one of the foods rather then a spreading illness of some kind. I’ve seen dry foods cause similar symptoms in guppies where they bloat, swim funny, then pass away shortly after. It expanded in there stomachs. If it were me, through process of elimination I would try to narrow it down. Perhaps quarantine and medicate a single fish you notice the onset of the symptoms in in a separate tank with separate equipment. If the meds help you will know it’s illness related. Try feeding the same diet but perhaps allowing dry foods to soak in the tank water outside of the tank shortly first so they expand before they are eaten. You could take it a step further and through process of elimination see if one of these foods is what’s the culprit as well. These are just thoughts, parameters look fine, and honestly these foods are high quality as well so it is a bit of a mystery to me as well…