20+ Dead! Help

[Hughesy]

Need desperate help!!

Ok my tank has been up and running for about 12 months and everyone was living fine.

On sunday we added 2 new aluminium catfish
and 2 other catfish (dont know there names) from PetsatHome (I know that was probably the reason)

Monday - 1 new catfish died, but couldnt find him anywhere. Eventually he surfaced on tuesday.
Following this :
Tuesday - 8 guppies and 2 platys died
Did a water test - Amonia is at 0.25
Wednesday - 8 guppies died
Did a 50% water change - amonia still the same the next morning.
Thursday - 5 guppies & 1 platy died
Friday - 2 guppies so far

Any ideas anyone? Since Wednesday we have been adding abit of methalyne blue - but im concerned it will effect the african dwarf frogs we have in there??

Please help

 

[Hughesy]

Any ideas please?!?!

 

[rust81]

You sound like you are having a more serious version of the problem that i was having at the weekend. Have you removed all the dead fish? These will be making your ammonia levels spike, which in turn will affect the other fish in your tank. You need to keep doing water changes to get your ammonia down to 0. If this increases at any time then you need to get it back down to 0.

Also, if i am correct in thinking, then methylene blue can affect your bacteria in your filter - so you will definitely need to keep an eye on the water stats. You may find that this is what is killing all your fish

 

[mikev]

Meth Blue affects the filter at high concentrations. If the color of the water is light blue, the biofilter is probably ok, but it is only marginally effective against pathogenic bacteria. With dark blue, it will wipe out essentially all bacteria, including both the biofilter and any pathogens in the water. It will also destroy some of the plants. Generally, Meth Blue should not be used unless there is a good reason to suspect a very dangerous bacteria in the water (like drug-resistant flex).

Keep checking the water parameters at least daily (better every 12 hours) so you can react if the biofilter gets damaged.

To OP: sorry for your losses and hope the rest of your fish makes it.... To avoid this type of events, QUARANTINE!