Emergency - dying fish, others gasping for air, foggy eye

[enigmatic]

I've been keeping a low profile on the forum for some time as everything has been going great until tonight.

When I left for work this morning, I believe all the Discus were fine but when I got home this evening I have at least one dead Pigeon Discus and a dead flying fox. All the others were gasping at the surface and whilst the catfish were still lurking they occasionally dashed to the surface before going back into hiding.

I've not changed anything on the tank for some time. Did a 40-50 % water change on Sun as I needed to move the tank out from the wall as we have decorators in who need to paint behind the tank.

My wife says the decorators haven't been near the tank today and had dust sheets over the tank yesterday when they painted the ceiling.

Ammonia level is fine at 0 PPM but nitrites and nitrates have both shot up. Nitrite looks to be 5.0 PPM and nitrate between 10 and 20 PPM.

Tap water reading appears fine.

I've been able to transfer all but one Discus to another tank at present - one is lurking where I can't get to it.

I've done a 50% water change and treated the tank with Prime (15 ml which is my regular dose). Will dose stability later.

Of the Discus I've transferred has a cloudy eye but seems to be perking up in the other tank. The transfer wasn't ideal as the other tank wasn't set up for Discus and is 5C cooler than what they've been used to.

What can have gone wrong and what else can I do to get the nitrite down in the tank?

TIA

Chris

[enigmatic]

Also, another of the Discus that I transferred out the tank has a white stringy slime on it in places.

[fishgeek]

something in the water
either fumes pumped through with air pump
spills off old used dust sheet, drops of paint thinner etc etc

lots of water changes
increased aeration
salt will help with shedding mucous, any damage and osmotic stress so dependant on how that looks

carbon or active polyfilter(resin that absorbs) to try and reduce whatever has gotten in there

andrew

[ILLUSN]

salt will also help detoxify the nitrite.
my money would be on fumes being sucked up by the air pump.

catfish air gulping as you've described is assosiated with low oxygen in the water.

[fishgeek]

i think the salt and nitrite is more to do with ion exchange across the gills rather than specif detoxification of the molecule, or is that what you meant

either way the prime should help with it

andreww

[enigmatic]

Thanks for the responses. I've done the water change on the main tank that was affected and the one Discus that wouldn't budge seems to be happy - not coming to the surface.

My Peppermint catfish have put in some normal appearances so appears to be OK. Will continue to monitor tank parameters and further water change tomorrow.

As to the Discus that were transferred, they seem to have perked up but not really interested in food. Have added salt to the tank they are in and further aeration.

Fumes would make sense as there was a very strong smell when I came home today from the undercoat being used. All the doors and windows were closed today as the aircon was on due to the heat. I guess with the main tank having the largest surface area, it was the one to pick up the most of this in the gas/water transfer.

Are you able to advise on the cloudy eye or do you think this will improve?

[ILLUSN]

thanks andrew, thats what i ment, stops "brown blood disease"

I'm sure the cloudy eye will improve as the fish improve.