I have been keeping my fish for more than three weeks now. I have already changed the water couple of times.

Yesterday what I did was
1. Vacuuming the tank
2. Change water 50%
3. I have notice that my pleco always sit under or over the heater so I decided to raise the water temperature form 70 F to now 75 F
4. I have rena Xp1 in my 30 g long..I decided to add another filter Aqualclea 200

After I finished these it was all well and fine. Nothing seems to be out of ordinary but in approx. four hours letter my fish BN Pleco was dead. I wonder what did I do wrong to cause all this? It was a baby about 1.5 inches

Any idea please? I just don't want get another one till I know what I have done wrong. It has been in my tank for more that three weeks and no any sign of trouble till yesterday. I have 6 zebra danio, 2 platy, and 4 tiger barbs doing fine. I have checked the nitrite, ammonia and ph yesterday and today this evening. Is all as usual ammonia 0, nitrite 0, ph 7

This post has been edited by LynnJ: Oct 29 2007, 09:58 PM

Hmmmm very odd, deffinatly no signs of disease or stress?

you say had done a 50% water change , what temperature was the water going in?

How do I know is stres? diseases the other still doing fine and I am sure if I didn't touch that tank yesterday I guarantee this fish would have been alive today. I just feel bad and I know is my fault.

At the time I was washing the tank I took them out of the tank and I put them in a bucket with the same water from the tank. This is the first time though to take them out. I treated the water with stress coat before I put them back but I didn't add stress coat while they were in the bucket. I thought the same water from the time would be okay..I don't know...I wonder if the stree killed my fish.

It was almost the same temperature but then b'se I changed the temp later it went up to 74 F and now 75 F but they were already in the tank then. So I was hoping the water temperature graduately raised while they were in there.

This could be a major issue here. Unless you are doing something that cannot be done arround fish, then leaving them in the tank is always the best option. Remoing your fish puts them through quite a stressful experience. Here is a link to tank maintanance; linky, and for further reading, see here. There is a lot of reading material there, and it may be confusing at first, but once you get your head round it, you'll understand better the processes occuring in your tank to keep you fish healthy, thus enabling you to ensure their wellbeeing.
Dont worry too much about the death, there was noting you could have done at the time, as you were either acting on bad advise or a lack of advise from your fish shop. Unfortunately, this is the norm within the fishkeeping community, and is the caurse of many tanks beeing sold second hand.....

Hope those links helped you, and that you can quickly pick-up the information you need.
Rabbut

Thanks I will read and see. Honesty I have never read any article on how to take care of a fish tank. Thanks so much.

no one has asked for your ammonia and nitrite / nitrate levels yet.

Has the tank cycled ?
http://www.fishforums.net/content/New-to-t...shless-Cycling/

Beat me to it. Did you cycle the tank?

If not that could be the reason rite there.

The tank appears to be cycled, if the water values quoted in the origional post are correct. What type of test kit are you using? I ask, as liquid tests are more accurate than dip strips. Dip strips give an idea of what is going on in the tank, nothing more, and the results by no means can be trusted as accurate.

HTH
rabbut

I think the problem is when I took my fish out of the tank at the time I was cleaning or the water temperature was slightly different as someone mentioned before. I tried to make sure that the water was as the same temp as in my tank but I changes more than 50% at once. I read from the link given above and I think this could be a problem too.

I cycled my tank and there is no problem of nitrite or ammonia for now. I use the API test kit.