help I had 7 goldfish and yesterday i found 2 dead and 2 disapered, i only have 3 left whats happene

i have a 3 foot fish tank with a lid so they did not jump out i had the 2 i found dead for 5 years and the others i have had for about 3 weeks which 2 disapered please could any one help me

Chances are the carcass of the missing fish was eaten. The fish probably did not attack it. They just ate it once it was dead.

You had the other ones for a long time. Here are some possibilities for your fishie mystery.

1. Your old fish had a nice little balanced system. The three weeks would be about the right amount of time for the added waste to cause a spike in your ammonia. There was only enough bacteria to support your original babies. The new fish threw your water chemistry off.

2. Old Tank Syndrome- I know we have all heard of Syndrome- but, Old tank is common too. Essentially there is something unusual about your water chemistry. Maybe a river rock is slowly leaking a chemical, or high salt concentration. Your fish that have been in there for a long time slowly adjusted to this strange water condition. They are fine. Whenever you try to add new fish though they don't make it past a month. The difference in water chemistry is too much for them to adjust to quickly.

It could also be a combination of the two.

Your new fish may have also brought in a parasite, fungus, bacteria.

That really sucks. I would let the tank sit for a little while, do a 25% water change every 4 days or so and keep testing the water.