Unresolved my Fish dying from on minut to the next!?

Hi i have 3 fish tanks a 29g 55g and a 46 bow front. my problem is with the 46g that i started about 9 weeks ago the setup is a rena canister filter thats good for a 175g in the filter i have activated carbon and bio bolls and sponges in the tank i have a heater and a power head and 40 pounds of live sand and some dry coral for decorations.

i also have
1 maroon clown fish
1 Ocellaris Clownfish
1 Yellow Damselfish

these 3 fish i have in this tank for 4 weeks and are doing well the problem started when i add any new fish to the tank it can look fin after acclimation but the next day or tow they just DIE but the clownfish will still be ok and i test the water ammo 0 nitrite 0 nitrate 20pp ph 8.2 tem 80 .

someone please help me diagnose why the fish are dying im going crazy not knowing what triggers the fish to die and only the clownfish and Yellow Damselfish should live.

 

You have very aggressive fish in your tank, they may be killing any fish you add.

 

also are your fish are very hardy and capable of surviving aweful water parameters, i think your adding more delicate fish and they cant handle the bad water quality like the fish you already have can so they slowly die off.

i would suggest getting a sump or fuge and doing weekly water changes. canister filters take an insane amount of upkeep to be efficient.

 

+1

The damsel and the maroon clown are most likely the cause. I had a zebra damsel in a 29 gallon, and one day I came home with a Royal Gramma. Within 2 hours, the gramma was dead and half eaten.

 

i added a Picasso Triggerfish he didn't lase 2 days and its in the aggressive category?

 

2 month old tank?has it cycled?could be part of the problem?

 

Any new fish is going to be very shy and attacked by the other fish. You may have other diseases that the current fish have developed immunity to.

Tell us about your acclimation procedure.

 

damsels will be aggressive but i definitely think water quality is the problem here, triggers are just a tiny bit more sensitive to quality than damsels but its enough to make a difference between life and death. a trigger wouldnt die that fast if he was being bullied i believe, and you would have noticed the bullying.

 

all the test show good results.

 

what all are you testing?