Fish Dying Daily - Water Tests Perfect.

[TRAGICTRAMP]

Ok well over the last 7 days every day my fathers tank has seen a lot of deaths, sometimes with bight marks, and now just wilting till they die or are humanely killed, at 1st it was 1 neon a night, so we got rid of his small talking catfish then his peacock eels, then the firiest kribensis, this proved to be pointless as then deaths ocurred without any physical damage and just their condition would deteriorate. so far he has lost about 10-15 neons, male fighter, 3 female fighters, and another female looks like its on its way out. the water tests daily are showing 0 ammonia 0 nitrite and 10-20 but i have done large water changes on alternate days with 20% on the others using prime as a dechlorinator and temperature matched. The tank is 150 litres being filtered using a fluval u3 combined with a rena xp2, 2 airpumps/stones. The stock left are about 8 neons, elephantnose fish, 1 golden barb, 2 apple snails, 4 rabbit snails, 3 chain loach,hoplo catfish, 1 bulldog plec and 2 baby bristelenose plecs, I treated the tank last night with interpet anti internal bacteria medicine in case their was some kind of internal disease, but since then a male fighter has died and a female is on its way out, we use the same frozen food on his tank and my 2 tanks and my tanks are 100% healthy.
 
Any ideas, i know that the snails, loaches and elephantnose make it very hard to treat the tank as a whole and with it being quite random which fish will strike next, their is no point in running a quarantine tank, and i hardly want to put any of his fish in my healthy tanks in case of spreading anything.
 
The problem seems to have stemmed from him adding a pair of gold rams, 1 died within hours and the other started to suffer and i moved it to 1 of my tanks and he appears to have recovered, the fish store replaced the ram for a hillstream loach which also died within a day of adding, i also bought a pair of these rams at the same time and they died within hours also and my male kribensis was ill for around a about a day, so im thinking their tanks/fish were infected with something which has spread. I have been their since and saw lots of dead or dying fish.
 
Any ideas/suggestions, their seem to be nothing external other than loss of colour in their final hours and i noticed the male fighters excrement was of a whitish colour last night before he died today.
 
thanks

 

[BerryAttack]

well something isn't right, by saying they are one their way out.. can you describe what the fish looks like the details any discolouration, heavy breathing, anything on the scales, fins not right, bloating?
 
are you treating the water before adding it in? how long has the tank been set up?
 
is the type of water when adding different from your tank? tap water or bottle water? 

 

[TRAGICTRAMP]

fins look fine, well saying that the male fighter was only using the 1 side fins last night, no bloating, no discoloration until their final hours, water treated before adding to the tank via bucket small drops of prime measured out, temperature matched with same ph as the tank, the tank has been set up for about 8 months, it was overstocked until this outbreak,  breathing is fine, i just checked on the ill looking female and it looked like she was having a chill as when i nudged her she swam around in perfect condition. Its tapwater but the same as i use in my tank.

 

[This Old Spouse]

I'd say shop at a different LFS. Did you add a bunch of fish all at once?

 

[TRAGICTRAMP]

well he went to maidenhead aquatics were he bought all the female fighters and all their stock have died also, they are giving him a credit note as obviously they are diseased but i still dont know why he had deaths before he added then.

 

[mark4785]

How are the oxygen levels in the tank? Do you have good water surface rippling to aid oxygenation?

 

[TRAGICTRAMP]

How are the oxygen levels in the tank? Do you have good water surface rippling to aid oxygenation?
 
yes external filter aimed to break the surface as well as 2 large airstones running off seperate pumps, it has to have a lot of movement/oxygen for the hillstreams and its also planted.