I have lost 2 adult duboisi and 2 young frontosa in the last couple of weeks and i have not done anything different in my tanks. My old man also lost a couple electric yellows and blues and my brother in law has lost a few dolphins and blues. All the fish were healthy and no changes to their diets or water changes etc. I am wondering if it has something to do with the low water levels in the dams and extra additives. My duboisi i was worried i had bloat but 1 girl has a mouthfull and the other dozen are fine and the ones that died were also fine the day before they died.
We went through something similar a couple of years ago when our supplies were down in the water catchment they do seem to add larger quantities of chlorine for some reason when they go a certain level in the dams also they add other chemicals the best time to do wate changes if you can is mid week as this is usually the lowest consumption rate so the water stay in the pipes longer and chlorine loses its strength especially if you live in a touristy area like I do. Also check to see if the council has scoured the pipes lately as this also can affect the water quality. Just a thoguht any way.
Not sure if this is the cause, but refer my post here:
http://www.qldcichlid.com/modules.php?name=Forums&file=viewtopic&t=1781&highlight=
yeah same thing happened to me. Lost a Bircher and a batch off flowerhorn (Gold Texas) eggs fungused within 3 hours of doing a "normal" water change. Started throwing in extra dechlorinator, but damn it sucks.
The Brisbane Shire has chemical levels topped up after rain so that may be your cause. They also use chloramine which is a mixture of chlorine and ammonia. So either ageing your water with an air stone for a day or 2, using a neutraliser which drops chlorine and ammonia levels in a bucket with the water you are going to add to the tank to let it do it's job with sufficient time or the above neutraliser and reducing the flow rate of the tap you are filling your tanks with to let the neutraliser do it's job without harming the fish will see you right hopefully. Or if you've got a mate who lives in the Pine Rivers Shire who'll let you use their tap water to fill your buckets may be the answer as well as it's only up the road a bit and they don't use chloramine. Hope this helps.
Cheers,
Bryce.