Why Are My New Additions Constantly Dying?

[Fluval-1200]

Over the year or so ive been adding new additions to my tank. My tank is severely understocked with only 8 torpedo barbs a sailfin pleco and 2 kuhli loach. Ive been buying new fish and holding them in a qt tank for weeks upto months using a mixture of main tank water and fresh tap water. Never bringing there water into contact with my main tank.
 
I put them into my new tank and within 2-3 weeks they are dying, no illnesses no fighting just dying. Its been from kuhli loaches to sharks and they all just die.
My main fish are fine and in brilliant condition as is my tank parameters. My qt tank was also constantly in good condition.
 
So what is this from? getting annoying as my tank looks bare and I cant seem to add anything....

 

[Dreamer03]

How many gallons is your tank? And the water paramenter? Also what kind of fish have you tried to add i to the tank?

 

[DiddleBug]

Yes, your it's probably your water that is causing the problem.  I have had the same thing happen to me.  Best thing to do is stop adding fish and do some water tests!  

 

[N0body Of The Goat]

Could be critically different water chemistry between the tanks.
 
Could be your cichlids are not taking kindly to new "invaders" to their home.
 
What fish have you been buying?

 

[star4]

I agree with Nobody, if you are adding water from your main tank to the QT tank then its not a water problem. 2-3 weeks dying after being added to the main tank could be stress related. Do the new fish feed ok when they go into the main tank? I am guessing the Kribs are a breeding pair from the tank of fry, my money would be on those stressing the new comers, the other fish are "use" to the kribs and keep their distance. One possible way around this is after you have QT'd new fish, put the kribs in the QT tank for a week and let the new fish settle in then add the kribs, its not a guarantee that it will work, but it would give the new fish a chance to explore and find places to hide.

 

[Fluval-1200]

Please read my post not my sig, the sig is false and I cant change it. Tank is now bigger and my stocking levels are in the first post.

 

[nic1]

How many fish do you add at one time? I once read that your tank is only cycled for the number of fish it has in it, then when you add more fish obviously the ammonia is instantly higher so your tank has to adjust again, don't really know how accurate this is, but I guess it's one of the reasons why we are advised to stock sparingly and slowly.
Also I agree with the chemistry difference in between tanks, especially ph as Many things can alter this such as bog wood, plants substrate etc. Maybe try and get your qt tanks water levels to match yours by adding some of the decor from your main tank into the qt tank and test the water in both tanks matching them as closely as possible.
It could also be stress from moving to their first location to the shop then to one tank and another with in a few months.
But after all that it does sound strange.... You should do a test and put a divider in and buy 4 of the same fish that you want and place a couple on one side of the divider without the current inhabitants and a couple on the other, if one side dies with the current fish then you know it's because they are being killed. If both sides die then it's a water issue....

 

[Fluval-1200]

Im only adding 1 or 2 fish at a time. The qt and main tank are literally identical parameters, I do a 50% water change on the qt tank using 25% main tank water and 25% fresh.
 
My current fish are pretty chilled, the new additions would be the ones to cause problems but I never seen any fighting/chasing or any other behaviour. 

 

[nic1]

Do you buy them from the same store?
Would you think it would be cheeky to ask them for a water sample so you can see how different their water chemistry is to yours? Might be worth a shot....

I only mentioned the divider as other posters on here said about fish not being kind so it would of proved a point,

Erm, trying to think really as it is strange, can be a case of the old fish being custom to the tank and the new fish not being used to something in there,
Also, is there any chance of contamination.... Say if you net the fish to move them, where does the net go? Any chance it could of been placed on any chemicals, cleaners, or if you float the bag, do you put the bag on the side for a bit unknowingly putting it a substance like surface cleaner...

There's lots of little things that should be considered, but I would ask for a shop water sample also.

 

[coolie]

Just to throw into the mix of ideas, are the new fish being beaten to the food by the others and consequently not getting a good diet? For example some fish are simply quicker on the food, Khuli loaches might now get any as they need sinking food, and no flake reaches the bottom uneaten.

 

[N0body Of The Goat]

You have still not told us what species you are trying to introduce to the main tank.
 
Quarantining for just 2-3 weeks is still pretty conservative in my eyes, especially if the new fish are species reknowned for not adjusting to hobby life (eg. Chaetostoma spp.), or they arrive half-starved at fish stores (eg. Otocinclus spp.). Quarantining is not just about looking out for illness, its also about getting new purchases to recognise and readily eat the foodstuffs you offer.

 

[Fluval-1200]

Kuhli loach, torpedo barb, garra ruffas, rainbow sharks and loads more all bought from different shops. Most from the shop I originally bought my main fish.
 
They all eat in qt and main tank, I actually overfeed to make sure my bottom dwellers have a good meal. My latest fish has been in the tank for a good month or 2 and today has died. My original fish are still intact (8 torpedoes, sailfin and 2 kuhli)
 
Still remains a mystery as I have no illness, brilliant water (tested on 2 kits) and no aggressive behaviour.

 

[coolie]

Just maybe there is something wrong which is tolerated by fish used to it and not under the stress of a move, whereas newer fish are knocked out by it. I'm talking toxins or bacteria.

 

[Meeresstille]

What are your nitrate levels? Could your main tank be having old tank syndrome?

 

[Fluval-1200]

Nitrate is like 0 to 0.25.
I was thinking toxins from the fish but I was using main tank water in my qt water changes, they last longer in qt then main.