Why Are My New Additions Constantly Dying?

[yinyangpete]

I read your post this morning and I've been mulling it around all day. I suspect that water quality issues, as far as what you are testing, are a red herring. Just my gut reaction based on what you've said.
 
Nonetheless, there are clues being missed. All really good mysteries are eventually solvable, right?  

 
Do the fish look fine one day and show up dead the next? Are there any outwardly visible symptoms that are evidencing themselves so slowly that they are being missed?
 
As far as aggression, I used to swear that my cichlids would wait until I left the room to be bullies. I would peek around the corner and catch aggression that I would never see when I was standing in front of the tank.
 
Keep some notes and don't take anything for granted. I hope you'll keep us updated with as many details as possible.

 

[Fluval-1200]

Sorry I seemed to of abandoned this thread lol.Last time I posted I had put my sponge filter into my main tank to suck up some bacteria, was around 2 or 3 weeks ago.
Today the qt tank was setup with that filter and water from main tank. Ive also added 7 neon tetras and 1 algea loach thing.
Il keep this thread up to date as much as possible as I would like to fix this weird issue im having.
 
Had a look at my tank and I have green bush algea which from looking online is from low c02 not enough flow and low nitrate. My flow is good if not abit to much but my torpedoes love to swim in it so il leave that, c02 ?hhmmm im not messing with c02 gear again and low nitrate which I have. The cure for low nitrate was water change? lol surely that's going to remove it and im not going to drag my water changes out anylonger.
 
Basically I need more fish to make my tank dirty or that seems to be the case.

 

[Mamashack]

Depends on the nitrate content of your replacement water - mine used to be quite high at 20ppm but now it's only 2.5 ppm
I don't have the space for elaborate or DIY set-ups so a few weeks ago I started adding Easy Carbo for the carbon instead of CO2 injection and APF liquid NPK fertiliser and my algae and melting plant problems have reversed.
Did you see if the filter had gathered enough bacteria by challenging it with ammonia before adding the fish to see if it could cope with the waste?

 

[Fluval-1200]

The filter has managed to cope with a sailfin pleco for 2 years lol, I don't think a couple extra small fish would cause an ammonia spike enough to kill them.

 

[Mamashack]

The filter has managed to cope with a sailfin pleco for 2 years lol, I don't think a couple extra small fish would cause an ammonia spike enough to kill them.

My mistake - I thought you'd said that you'd put the filter sponge in there for 2-3 weeks to soak up some bacteria

 

[Fluval-1200]

O sorry I thought you ment the main tank filter lol. Never tested the sponge one as I don't have any ammonia, il check the qt tank for ammonia tomorrow.

 

[Fluval-1200]

All going well so far, no ammonia in qt tank. Nothing drastic happening in main tank either, just black bushy algea?
 
33% water change on main tank very week.
 
25% water change every 2 days on qt tank using tap water.

 

[Fluval-1200]

Months down the line, 4 new torpedo barbs in with no problems a new loach with no problems. Weird....