How long after not acclimating will fish die?

Miami Reef · Apr 1, 2021

I purchased a lot of fish at one time 2 months ago and more than half died about 2-3 weeks later. Including one or two of my older fish.

I’m trying to learn from the mistakes I made so I don’t repeat the mistakes. Looking back, I made a lot of errors that could contribute to the death.

before I got the fish, I redid rock structure. Removed and added some dry rocks.

I added a lot of new fish and I acclimated them prior.

Algae was blooming crazy so I overdosed vodka (big bacteria bloom) and lanthanum chloride. Fish didn’t die right away. It took about a week or so after to die.

I have a blue tang (he was an older resident) and I saw some ich on him but he recovered (I know that means that the ich is in the egg cycle now.) No other fish got ich but a lot of fish died.

The mistakes I made were changing the rocks and adding fish immediately afterwards.
Overdosing the tank

I don’t know if I had ammonia or nitrites because it kept showing 0. Max was .25 on API.

Maybe the algae was consuming the ammonia which means that is was undetectable to the test but lethal?

No fish have died recently. I have some new fish. Most of the old fish survived. Only a mandarin fish died that was an old resident.

It took about 2 weeks for them to die after being added.

clown tang, and angel fish were the most affected. I have an older scopas tang right now and he didn’t die from the lanthunum chloride.

Do you think I didn’t acclimated them long enough? How long after bad acclimation will they die?

Tank is 300 gallons and I was established for 2-3 years with rock from a previous 300 gallon tank from 8 years.

Idoc · Apr 1, 2021

1. Large dump of a bunch of fish into a system can throw off the balance...but a 300g tank is pretty big and should be able to handle this when the tank is years old. Probably not the issue...
2. Carbon dosing a bunch and adding LC at the same time...huge bacterial bloom will deprive the water of oxygen...definitely can cause a die off.
3. LC can drop alkalinity very quickly if added too quickly...typically more effecting corals, though.

Hard to say exactly... Basically, maybe go slower next time, quarantine the fish for a month prior to adding to the main tank so you can pick up on problems before wiping out your entire tank.

hhaase · Apr 1, 2021

There are unfortunately a lot of possibilities. How many fish were "a lot" that you added at once, and how many did you lose? If there's too much loss, things can cascade pretty quickly, particularly if it's not obvious right away there were losses and fish start to decay and spike the ammonia. You'd be surprised how short an ammonia spike can last in a large established tank, and nitrites are far more lethal but disappear quicker. Sometimes you can catch the 'shadow' of the event in a rapid rise of nitrates.

The carbon dosing and oxygen depravation are a strong possibility as well, did you possibly have a big pH swing that would indicate a large shift in co2 concentration?

Did they slowly wither away? Were they suddenly all deceased on the bottom/top of the tank when you woke up? Any strange activity from them such as flashing, gasping, injuries, discoloration, bloating, etc?