I have used epsom salts for bloat/constipation before on discus I dosed the whole tank and raised the temp a couple of degrees. It can take 48 to 72 hours to completely clean out the fish. I use 1 tablespoon to 20ltrs of water and do water changes daily adding more epsoms salts to replace the stuff taken out in the water change. Also brine schrimp are great fibre for fish I give my fish live brine schrimp twice a week. Hope this helps.