Ally my fish have started dying in last two hours

[rascaluk]

Hi, I've had a 120l tank set up for a few months now, couple of clown loaches, five glolight tetras, golden gourami and a couple of platties and a plec...

THis week I introduced three glass catfish. Last night I noticed all the tetras were up near the top which was unusal but after a while they returned to their normal haunt.

Now in the last two hours all five tetras have died, the platties are on the verge of dying, my clown loaches are greyish and my plec isn't eating. ALso one of the glass cats is dead so I think it's possibly the culprit.

The water tests fine for ph, Nitrate and Nitrate but I;m a bit stunned by the speed of all this. I've put Melafix in and moved a platty to another tank on its own and turned all the lights out and covered them.

Any ideas folks, I fear I'm going to lose the lot.

 

[The-Wolf]

The sudden death of many fish over a short period of time with few preceding symptoms. Surviving fish hang around the water surface / stay on the bottom and may lose equilibrium. They are lethargic and don't eat.

1) Acute poisoning. Water should be tested for core parameters and fish examined for signs of severe parasite or bacterial infection. If possible, post mortem recently dead fish. If these are negative carry out a 75% or more water change on the presumption of some (as yet, unknown) toxin.

2) Hypoxia (Low dissolved oxygen levels. )

3) Peracute bacterial disease. Diagnosis would require post mortem and aseptic bacterial sampling of organs

From www.fishdoc.co.uk

As you say the water is fine, I'm guessing it is either option 2 or 3

 

[jsa500]

Hi,
Sorry to hear about this. I have just lost most of my fish and I suspect it is for the same reason you suspect, disease carried over by one of the new fish. I suppose this goes to show how important it is to quarantine our new fish.