help - poisoned fish

[Carcharodon-carcharias]

as the title says, I woke up this morning to find 3 of my 4 fish dead

on monday I did a 30% water change which I do every week, by tuesday the fish were acting very ill - the goldfish were crashed at the bottom of the tank with their fins clamped. I took them both out to look at them and saw no physical signs of injury. I then did a 50% water change (as was reccomended to me by a fish keeping friend) and removed and cleaned all the ornaments. When I woke up this morning they were dead. The friend mentioned earlier has said they think they were poisoned by something possibly in the water.

But my problem is that my plecostomus (a chocolate albino) is still alive. I don't know now what to do in order to make sure the fish doesn't die. I have removed it from the tank and for the time being it's in a bucket with fresh water. I'm trying to keep the temperature constant but other than that I really don't know waht to do, obviously I can't put it back into the tank untill it has been cleaned and I find out what killed the other fish. Any advice or information would be serioulsy helpful as I really love this fish (as I did all my others )


btw it is a 200 litre tank and the goldfish were about 6inches long and 4 inches long. The pleco is about 5 inches long.

 

[jlk]

Im SOO sorry! We need to figure out what happened here so lets start at the beginning. Is your tank cycled? How are your water parameters for both your tank AND your tap water(amm/nitrite/nitrate)? What are you using as a water conditioner (new or different than usual)? Did you temp match your water? Is there ANY possiblity of your tank being contaminated with something (someone used something like febreeze or carpet powder in the room where your tank is) or someone cleaned the glass? Did you change a filter or some other aspect of your tank (new decoration or plant or fish)? Did you wash anything you use to change your water recently? Im trying to think of other possible sources of contamination here but lets start with these questions and try to figure it out!

 

[jlk]

Food is another possibility- did you (or anyone else) feed them something different or new or perhaps something got into into your food source (sprayed, spilled or otherwise)?

 

[Carcharodon-carcharias]

Im SOO sorry! We need to figure out what happened here so lets start at the beginning. Is your tank cycled? How are your water parameters for both your tank AND your tap water(amm/nitrite/nitrate)? What are you using as a water conditioner (new or different than usual)? Did you temp match your water? Is there ANY possiblity of your tank being contaminated with something (someone used something like febreeze or carpet powder in the room where your tank is) or someone cleaned the glass? Did you change a filter or some other aspect of your tank (new decoration or plant or fish)? Did you wash anything you use to change your water recently? Im trying to think of other possible sources of contamination here but lets start with these questions and try to figure it out!

Unfortuneatly the plecostomus died :'( It was red when normally it is orange and its fins looked damaged, I dont know if this supports the poisoned theory or not, but the fish looked perfectly healthy monday night.

My tank is cycled and the fish have been living happily in it for around 6 months (the goldfish for about 18 months). The water in my tank seemed good but when I did the water change is when the fish got ill so there might be something wrong with my tap water. I treated it with the stuff I've always used :/ we've taken a sample from the tank anyway and we're going to have it tested at a fish shop to see if that answers the question.

about a week ago I added a new fish (a weather loach) and I bought some bogwood for my pleco, so something might have come into the tank with them :/. either the water or the new fish are the only ways I can think of that anything could have gotten into the tank as I'm the only person that cleans it etc.

I'm completely gutted about my fish and I really want to find out what happened so I can avoid it in the future.

 

[jlk]

Thanks for the info! We need to look at your water parameters (amm/nitrite/nitrate) for both your tank & your tap. What i am suspecting may have happened is that the addition of the new fish may have been more than your tanks bioload of bbacteria could handle and it created an ammonia/nitrite spike which was lethal. I do not know this absolutely because we dont have the water parameters from the water the night your fish passed. It is worthwhile to consider investing in an Api fw master test kit so you can monitor your water in the future. Lfs generally use strips to test water-while strips are known for being inaccurate, it will atleast give us a better idea. Ask for specific numbers for amm/nitrite/nitrate.

 

[DragonFish71]

Have you had a lot of rain in your area?

I ask this because our water purification plant will add extra stuff to the purification process because of run off from rain/melting snow. That can cause your tank to crash. I have learned to add extra dechlor (prime in my case) to compensate for what they are adding.