Hi, I'm new to keeping fish. We bought all the equipment, waited three days before adding fish. We had four platy fish in a 27 litre tank. I carried out a water change after two weeks and everything seemed to be fine.
Three days ago, (9 days since last water change) the fish all started to look ill and yesterday they died.
I took a sample to the pet shop and they said there was lots of ammonia in the water but no nitrate or nitrite. Apparently the bacteria weren't present in sufficient amounts.
Can anyone help as my 10 yr old son is autistic and he's REALLY upset?
Do I empty and clean the tank, start the whole cycle again with fresh water?
Do I just do a normal clean of the pump and filter sponges, retest the water before getting new fish?
Did I mess up with the water treatment? It's called Tap Safe. I changed approx 1/3 of the tank, so 9 litres of tap water in a bucket needed 1ml of treatment. Did I do something wrong?
Is it worth buying water testing kits to use at home?
Most importantly: What've I done wrong and how can I make sure this doesn't happen again?

Eric

Sorry if this has been posted in the forum before but I couldn't see it in the recent posts.

Sorry to be the bearer of bad news, but 27L is not big enough for fish, shrimps and snails maybe.
The reason your fish died is because your tank wasn't cycled,
Please take a read of this article http://www.fishkeeping.co.uk/articles ... hless-cycling-article.htm
All the answers to your questions are covered in that.
Good luck if you decide to start again.

I'm trying to understand *why* the tank didn't cycle if the water treatment added the bacteria.
It was left for over three days at the beginning. Why didn't it (seemingly) start at all?
Did something kill off the good bacteria or is there another problem?

Hi, the treatment you mentioned was 'tapsafe' this removes the chlorine from the water making it safer for the fish,it does not put any bacteria into the water,
Did you use something else to cycle the tank?
The reason your tests showed No Nitrites or Nitrates was because there were no nitrifying bacteria present to convert the fishes waste (ammomia)to Nitrites then Nitrates.
I have used a treatment called Bio-mature in the past with good results, it would also be advisable to get a Liquid test kit such as the API one, Test strips can be a little inaccurate,
You would also be looking at about 4-6 weeks to cycle the tank. HTH.

I'll look into getting the treatment you mentioned.

The one I used was called 'bioactive tap safe' and the pet shop assured me it was the right stuff. They also told me I could add fish on day 3, turns out not to be the case.

It's a shame that this happens with Pet shops, some seem only to keen on taking your money,
Hope things go smoother next time,
While you are waiting for your tank to cycle you could research the fish you like and see if they will be suited to your water conditions, There are some Caresheets here
http://www.fishkeeping.co.uk/modules/caresheets/