Multiple Diseases

Do a very large water change if you haven't already done so.

But I doubt if the prospects are good, fish rarely seem to recover when symptoms have gone this far.

Ah Fruitbat, I'm sorry for your loss.

I did reply earlier but it seems to have disappeared or perhaps I forgot to post it.

I hope you get it sorted soon.  It's horrible when our fish become poorly and/or die.

When you do a water change, add enough of the med to dose the new water volume.

Have you ever watched any of the helpers doing a water change on your tank? I wonder if they are doing something they shouldn't. Eg forgetting dechlorinator, adding a lot of very cold water and not turning the heater back on till they remember a couple of days later etc.

You need to clean both tanks as water quality is one of the major causes of fish health problems. This is why I asked if the person looking after your fish knew what they were supposed to do.

With meds that are dosed every day, do the water change then add the med.
With those that are not dosed every day, do the water change then add the dose on dose days; on non-dose days just add the amount of med to treat the volume of new water - ie to replace the med you just took out.

hi, i think i have a problem with my mains water as it smells , it tests ok but maybe it has something in that my fishes don't like..  if i bought some still water and warmed it up that would be ok to use , 

hi, it smell off !!  no particular smell it just smells, not chlorine , maybe a hint of ammonia or drainy   i have put some water from my fridge which goes through a filter and left it overnight in a bucket ( thought this would be better) as this is normal tap water and hopefully this will be better, this should be ok shouldn't it

hi, not sure what filter is but checked ph and gh and kh etc against normal tap water and the same, I'm hoping it will filter out whatever is making it smell..would you try this or stick to normal water and do small water changes

hi, will do..  water doesn't smell bad just it has a smell when it shouldn't... I'm looking for reasons why my fish are getting sick but it won't hurt to ask them ..  thanks sue 

There is more than one type of filter. The most common one, as you say, replaces calcium & magnesium with sodium. But if fruitbat's GH is the same in both freshly drawn tap water and filtered water, it can't be that type or the GH would drop as the tester measures only divalent metal ions such as calcium and magnesium. Sodium in monovalent and won't show up in the GH test.

The Brita style filters exchange calcium and magnesium ions for hydrogen ions. With this type, GH falls as Ca²⁺ and Mg²⁺ are removed, and the pH plummets as H⁺ is greatly increased. The filter in question can't be this type as the pH would have dropped dramatically and fruitbat report no change.

There are other types of water filter, though, and this is why I suggested daily small water changes, the same as for bottled water. And it will need more small daily water changes as fruitbat goes back to tap water. By small I mean 10% or less.