electra yellows ( dead )

[very confused]

im wondering if anyone can help -- i have a 80 litre tank with 4 platties -- tank has been cycled for near 9 weeks -- temp is at 26degrees cel -- ph is 7
nitrates and ammonia has tested zero - plants are growing very well
the problem is that anything i introduce -- 1st attempt was neon tetras and a bristle nose ( with the the platties already there for a while ) they lasted a day -- retested tank for all of the above -- all came out ok -- waited for 3 weeks ( platties still doing fine ) then introduced 2 small electric yellows and another bristle nose all around the 3cm in length --- fed these flakes and bloodworms as before and now all have died -- one yesterday and the other 2 today -- it couldnt be that some how the platties are killing them could it --- now im to scare to introduce anymore fish incase they die and im none the wiser -- all water tests are still fine
and i have been changing 20litre of water each fortnight and adding water conditioner

 

[juanveldez]

that is really odd cause usuall a labidochromis cearlues is a pretty hardy fish. is there any salt in the water as I noticed that you have palties in there and since they are livebears I am guessing as I don't have a clue but that they like a bit of salt in their water.

 

[New Boy]

You mention that ammonia and nitrAte are zero, have you tested NitrIte?

Do you have anything in the tank that wasn't brought from an aquatic store of some sort - such as gravel or some rocks?

I doubt the yellows would get pushed around by the platies. Did you get all of the fish that have died from the same store??

 

[very confused]

the nitrite are also zero there is no salt in the water -- both groups of fish were bought from the two fish shops i always use -- and still the platties live on without a care in the world - but nothing else i introduce does

 

[CFC]

What is the pH of the water from the lfs? Could be the fish have died from pH shock if there is a noticable difference.

 

[andyt_uk]

i have had 7 neon tetra die in a cycled tank with no problems that also had 2 platty in it who live on without a care in the world.
the platty are now in the big tank, and 4 neon tetra survive in the small one

most of the dead ones appeared to have damaged fins though i never witnessed any bullying

 

[New Boy]

Neons can be quite sensitive but yellow labs are very hardy (although they prefer a higher ph to your tank it shouldn't kill them overnight). You mentioned that nitrAte was zero, there is usually some nitrAte in a cycled tank (as there is in your tap water too) - could your testing equipment be malfunctioning?

Could your temperature be dipping overnight?

Can you call the lfs to get the ph of their water?