why am i losing my fish????

[dolly_daydream]

hi
hope you guys can help me,(well you usually do)ok here goes,
i have 5 tanks all fully cycled and going great ,but the one in my bedroom im having trouble with its 130 litres and its a community setup,
with 10 danios my babies ,1 platy and 6 corys,and 6 neons,
the readings are
ph 7
nitrite 0
nitrate 10,
ammonia 0,
i do a 25% water change every week,
i have good filtration,fluval 4+
and a ugf,which you should agree is easily enough for my 31 inches,lol.i believe in over filtration and understocking..
this week im losing my fish,first i found 3 danios dead on the bottom ,then i lost a couple neons they was floating on the top dead,2 cory cats and 2 khuli loaches ,all with no obvious signs of disease,s,they was all eating,none had lost any weight and they all was behaving normally,but just before they die,they go underneath one of the caves and just die, ..i haven,t added any thing new to my tank,fish or ornaments or plants its been running great for months and months,i just feel so sad watching my babies die can anyone suggest anything???
i haven,t had any treatments in there either..
one thing ive noticed though this last month everything in that tank as stopped breeding,my danios,my guppys,(which died also)my platys everything,they stopped chasing each other and playing like they used to


thanks in advance for all your replys

 

[Angry_Platy]

Sorry to hear about your fishies dying....

You seem to have the environment in the tank covered....good filter, not overstocked, cycled, blah blah blah. Now look at outside. Have you been using fly sprays at all in the house? Had your carpets cleaned? Has the local water supply been adding anything to the water (you may need to call them)?.....that kind of thing.

I had a lot of fish die over a short period too...but only in one tank (I have 4)...all other tanks and fish were fine (including clown loaches which are HIGHLY sensitive)....a LOT of platies died, all me neons died and all my glolight tetras died....not to mention my glass bloodfin tetra...I have been keeping fish for 12 months now...all tanks are cycled with regular maintenance on filters and water changes etc

NE ways....I discovered the problem to be a dog toy sitting on top of the tank draping into the filter. Sounds innocent huh? Well, we realised that the dog gets flea treated every month...the dog rolls around the carpet with the dog toy....flea treatment goes on toy....toy goes into tank filter...flea treatment goes into the tank...

I removed the problem, did substantial water changes over a 5 days period...and now things are settling down. I still have the odd acting fish but all seems good.

Yeah, its a long story, but I guess what I am trying to say is it may not be realted to the tank "directly"....

Good luck and keep us updated