48 Hours, Fish Keep Dying

[Waffles]

Its' been 48 hours and I've lost one medium sized goldfish, and 4 different platty's. My water temp is fine, and I'm not over feeding them. I just changed the cotton inside of the filter and did a water change about two weeks ago. any ideas?

 

[onidrase]

you might have tossed a bunch of your beneficial bacteria by changing the cotton, which may have caused ammonia or nitrite to spike in the tank, thus poisoning the fish.

 

[N0body Of The Goat]

After those deaths, I would definitely be doing a big water change, at least 75%.

Up your "normal" (outside emergency) water change regime, 30-50% per week.


Water stats?

Tank size?

Numbers and type of fish left?

 

[Waffles]

The tank size is 25 gallon.Number of fish left is 4. One female swordtail, three platy's.

 

[Rummynose]

Did you cycle your tank? (where yo establish bacteria colonies in your filter, by either fish-in cycle where the fish produce the ammonia that feeds the bacteria or doing a fish-less cycle, where you supply the ammonia)

Don't listen to what the instructions say on the box regarding changing the filter media every so often! If your filter media starts falling apart just add new media to it, so it can be seeded with bacteria from the old media! Otherwise you lose your bacteria and have to cycle your tank all over again!

To maintain a healthy tank (after a tank/filter is cycled) it is recommended to do weekly water changes. Most people do between 30 - 50% every week.

Do you have a liquid test kit to monitor your levels of ammonia, nitrIte and nitrAte?