Sick clown loachies

[leeandvanessa]

I put a new filter in my 90L tank, all fish have died except 3 but they are lying on their side, panting. It is like they are paralyised. They have been like that for 2 days. I am concerned they are in pain, what should I do? All levels and temp ok and unchanged. Tank has been established for 3years.

 

[Mumma.of.two]

I put a new filter in my 90L tank, all fish have died except 3 but they are lying on their side, panting. It is like they are paralyised. They have been like that for 2 days. I am concerned they are in pain, what should I do? All levels and temp ok and unchanged. Tank has been established for 3years.

Hi and welcome!
Did you keep the old filter media and put it in the new filter? If not you have thrown your tank into a cycle. What are you using to test? You need To do a large water change with temperature matched dechlorinated water ASAP! Your fish are being poisoned by ammonia build up.

 

[Mumma.of.two]

Please read this. This is what is happening in your tank.
http://www.aquariumadvice.com/artic...g-but-I-already-have-fish-What-now/Page2.html

 

[leeandvanessa]

Thanks

I have done. I appreciate your help. I'm devastated. I shouldn't have listened to pet shop lady. In 8years of having these beaut creatures I haven't had a mass extinction.