Sudden sickness

[Tyminator]

One of my tanks is a 30gallon. In it are 2 adult blood parrots(prob about 3-4inches), two baby BP's a baby Frontosa, and two small Plecos. Not real crowded, and all the fish get along. About a week ago i noticed both adult BPs starting to act strange. Normally very cheerful fish, they were hanging out at the bottom of the tank, and always hiding. ( Looked like they were sick). Their color was still bright orange and would still attempt to eat. I figured, must need some water chages. But what was strange was all the other fish acted completely normal.
My temps were as they always were(77-82). The tank is well aged, and has some good green life growing up on top of some palm trees decor,towards the lights. I did a 20% water change, then 2 days later i did another. I put in a some new media in the hangon 30g filter(that is still working strong).
The smaller of the two BPs didnt make it, and the other is still not acting great. He has started loosing a little color. They were both a little less than 2yrs old. So im looking at him today, and i noticed that my tiny littly stary night pleco, or what ever it is, was dead as well. Im needing some help. Ive added some stress zyme and stress coat. Now im just waiting, and i would like to keep my big BP alive. Any help would be great
PS. all the other fish are acting and looking great, the nitrate was a touch high, nitrite was normal. Thanks

 

[SpeshulEd]

Did you replace all the media in your filter?

 

[Tyminator]

yes, after they got sick. they had lived in worse conditions than current with no prob. Before i got a 55g, i had 10 or more growing fish in there, so constant water changing was ness.

 

[SpeshulEd]

If you replaced all the filter media, all the good bacteria went bye-bye as well. With nothing in there to break down the fish waste, over time, the fish will become sluggish and die...because they're basically swimming in their own poo.

If you have another tank thats established take some of the filter media from that tank and add it to the tank in question to start breeding the bacteria. If not, then trying something like Seachem's Stability to get the bacteria going again.