fish are dying!!!

[expkeeper19]

so ive got a 20 G tank that i cant seem to keep fish alive in, its got a sand bottom, live plants, drift wood, a aqua clear 50 filter, temp is at 80F, the tank has alot of trumpet snails that breed like crazy, the tank is stocked with
3 cory cats(panda,jullii,green)
4 pristellas
1 neon(used to be 5)
2 glass cats(used to be 4)
3 harlequin rasboras(used to be 5)
used to have 3 german blue rams
tank also has 4 ghost shrimp, they are all doing fine.
nitrates and nitrites were slitely off, but i fixed that, the ammonia is fine, no fish has dropsy,fin rot, ich, external parasites, no bloating, no concaved stomachs,
i am in need of advice, i have been keeping fish for 8 years and this tank has stumped me.wtf.
any help would be appreciated

thanks

 

[FishingOut]

Can you post the results of the of the water test? nitrites, nitrates, and ammonia?
Your waterchange schedule? and how you do it.
And are you sure the rams are killing them off?

 

[McPhishy]

50% WC.

 

[expkeeper19]

Can you post the results of the of the water test? nitrites, nitrates, and ammonia?
Your waterchange schedule? and how you do it.
And are you sure the rams are killing them off?

i didnt say the rams were killing anything off. my and i dont have a nitrite or nitrate problem any more, everything is clear. all the fish where doing great for months and all of a sudden, in the last 2 weeks every thing seems to be dieing off fish by fish like one or two each day. i change the water about every 3 weeks, i use a gravel vac and sift it right along the surface of the sand picking up fish waste. i then add water to the tank, and add prime. the water temp goes down about 2 or 3 degrees when i do a water change.

 

[FishingOut]

When you say ammonia is fine, and nitrates and nitrites are a bit off, You can pretty much assumed you tank isnt cycled properly. Thats why I asked for numbers.

Nobody will be able to assist your with the information you provided.
Sorry i meant arn't. I simply asked you if the rams were killing fish off because they can get aggressive. Without you getting a water test and posting the results, or saying an symptoms your fish have is impossible to determine whats killing your fish. If everything was clear your fish wouldnt be dieing.

 

[expkeeper19]

the rams were a later addition to the tank but they were the first to die off, they started the chain reaction since they died 2 weeks ago everything els is going day by day, ill try to give you some sort of a reading for the nitrites and nitrates and ammonia but nothing showed up last time i did a test. but like i said the fish arent showing any signs of illness, they are all eating, they are all active, no bumps,fungesas,no dropsy,no ich, no concaved stumachs, it seems to be that each morning when i check the tank that i have one more dead fish, they die over night