if you have issues make sure your tank if properly cycled. Have a look on google for `nitrogen cycle`, its been a while since i have kept fish but i seem to remember it takes around 12 weeks.

Once you have done this start with just a few fish, to try and get the tank balanced. Im sure people will correct me on this as i might get the chemicals mixed up but....

Fish = Poop/Wee => Amonia (very toxic for fishes)
Filter Bacteria convert amonia => nitrite (a little toxic for fishes)
more bacteria convert nitrite => nitrate (safe for fishes)

When you are carrying out your water changes it is to get rid of the excess build up of nitrate.

When testing your water with your test kit, you should detect no amonia at all. The smallest reading is too much for fish. If you get any then carry out a 10 - 15% water change.

As a rule I used to have a 300l tank which was well stocked and I used to carry out a 10% water change every week.

With a smaller tank it is more practical and you could probably do 2 10% changes per week.

It can take a long time for a tank to become properly balance.

Once your tank is established, i know it is tempting but try not to introduce too many new fish at once. More fish = more poop which = more amonia. The bacteria will grow quickly but the overall chemical changes in the water can take a few days to balance out.

As a rule, when adding new fish test the water for a couple of days just to be sure.

I hope this helps........

Oh, a hint on decoration -

get some Java Fern & Amazon sword from your local fish shop. They are both very slow growing but look fantastic and dont really need any plant food. The fern needs to be secured to a rock/bogwood with string and the sword should be planted.

After a couple of weeks the outer leaves on teh sword will die, but strip them off and it will keep growing from that.

really nice relativley clean plant that will set your tank off :-)