Having Problems With 30 Gallon Tank, 10 Months Old

[Xena Daisy]

Hi,
i set up a tropical freshwater tank just under ten months ago and i seem to be having nothing but trouble with it, and many deaths! I left the tank to cycle and test the water weekly, all the tests show that the water is fine and does not indicate any problems, I proform a 6 gallon water change once a week (the tank is ten gallons) and i make sure the water is the same temperature, i also add cycle after adding new fish.
the fish do not show any signs of illness prior to dying,
the species i currently have in my tank are:
5 penguin tetras - recently lost one
3 black phantom tetras
one guppy - had numurous problems with guppys including fighting, i thought they were peaceful tank mates
two female siamese fighter fish
one albino cory
five neon tetras

over the life of the tank i have seem to have lost so many fish, including a male fighter which was not in the tank along with the females, two dwarf gouramis, its got to a point where i am afraid to put any new fish in the tank! Although not all the fish lost have been new tank mates some have been in the tank for almost the entire ten months.
i am clearly doing something wrong but cannot pin point it, i also have a ten gallon tank with one guppy, four cherry barbs and a male fighter fish in which i have never had any problems despite the fact that i treat both tanks exactly the same.

would really appreciate an outside view maybe someone can spot something i am doing wrong,
any ideas would be very gratefully recieved

 

[minxfishy]

Hi and welcome to TFF

First you say you do water testing, can you give us the water results you have currently, ie, ammonia, nitrIte and nitrAte as this will give us an indication if there are any water quality problems. Also what are you testing with, strip tests or liquid based test kits, liquid being far more accurate.

When you first cycled the tank, how did you do it, was it a fishless cycle using ammonia to replicate fish waste or with fish in in the tank. I suspect it was with fish in the tank as this is the advice usually given out by fish stores.

 

[Scotty001]

im not 100% sure but also adding cycle may also be causeing problems, i presume its a product used to kick start a cycle which means putting it in your tank sets off a mini cycle & when you get new fish it may be overkill on the bioload and ruin a good body of water causing the filter to strugle way too much. hopefully some one with more understanding of this product will come along.

As minxfishy has said if you could post your current water stats that would help alot.
Scott