Help! What could have killed my brand new fish?

Aquarist76 · Dec 9, 2019

Hello,

I got 4 tangs on Saturday from a sponsored seller here on this forum. I got a Koi tang, Salifin tang, Chevron tang, small Achilles tang. I picked them up from about 2.5hs away and drove them home myself. I acclimated them and put them in a QT and they seemed to be fine. About 12 hrs later when I woke up the Chevron wasn't doing well and died shortly after. No signs of any disease or trauma. I checked all parameters and everything was fine. I checked ammonia by 3 different methods as I figured that would be the main culprit and all came back normal. Salinity was 1.025 as measured on 2 refractometers. pH 8.3 as measured two different ways. No nitrites or nitrates. I put a dose of Prime in the tank just in case. A few hours later the Achilles and Koi went from swimming around perfectly fine to dead as well. I rechecked all parameters and still nothing. This morning I work up and the Sailfin was dead as well. I put a test fish in this morning to see what happens, haven't changed the water yet. So far after 15hrs he's doing fine.

The seller thinks it was an ammonia spike which I would agree as the most likely culprit if I didn't test 3 different ways and come up with nothing. The seller had treated with Mardel Quick Cure and was feeding the fish up to the time they were bagged up for me. I would have liked to see them maybe in slightly bigger bags. It took about 2.5hrs to get them home. The only other thought I had was ammonia built up in the bags and they got ammonia burns on their gills. I don't know if the Mardel could have made it more toxic. There was Mardel in the water of the transport bags.

The seller only has a live arrival policy so I'm SOL on about $1500 of fish, but I would really like to know if there's anything I'm missing. I've never seen anything like this happen before and I've been taking care of fish for about 3 years. I've never had a tang die from anything other than illness or trauma.

Gareth elliott · Dec 9, 2019

Mardel quick cure is formalin and malachite green. Both of these alone or together should only be used in bath form. Long term exposure can cause a myriad of health issues on fish and people. If i had to guess i would say chemical burns of the gills, inhibiting o2 extraction, exasperated by being in a closed bag. Given the short time frame you stated, my guess.

BeejReef · Dec 10, 2019

sorry about your fish. even in modest bags, I don't think you would expect huge ammonia buildup in a couple hours.
how big was the tank you put them in? How was the air exchange?

vetteguy53081 · Dec 10, 2019

Im thinking lack of oxygen in the bag and an ammonia spike making them somewhat lethargic.
You mentioned acclimation. By what means did you acclimate and did you net them to new tank or allow acclimation water to enter tank?
Transporting them in buckets than bags would have been my first choice. Im disappointed for you on both the loss of fish and the money spent

Aquarist76 · Dec 10, 2019

The tank was a 40G which I know is small (I ended up getting 4 fish instead of 2). There is the filter moving water, 600 g/h powerhead, and two airstones in the tank. I was worried about ammonia which is why I thoroughly checked the tank water. My plan was to do daily water changes until I could get a couple of them into a different tank in a day or two. No ammonia in the tank as tested by Red Sea test kit, ammonia strip check, and Seachem ammonia alert badge.

Right now I have a dottyback in there as a test fish and he's doing fine so far after about 30hrs or so in there.

I hadn't even feed the fish before the first one died so I wouldn't expect too much ammonia to build up in the 15hrs or so between when I put the fish in and the first one died.

Aquarist76 · Dec 10, 2019

vetteguy53081 said:
Im thinking lack of oxygen in the bag and an ammonia spike making them somewhat lethargic.
You mentioned acclimation. By what means did you acclimate and did you net them to new tank or allow acclimation water to enter tank?
Transporting them in buckets than bags would have been my first choice. Im disappointed for you on both the loss of fish and the money spent

Yeah, I didn't think to bring buckets which might have been better. I temp acclimated the fish in bags and then put them in buckets and added tank water in a fairly brisk fashion so as not to let ammonia build up. In the course of about an hour I turned the bucked water volume over 2-3 times before putting them in the tank.

Aquarist76 · Dec 10, 2019

As you can see, the size of the tank vs size of the fish really wasn't too bad in my opinion.

moz71 · Dec 10, 2019

I feel for you buddy!. I just finished a post where I did everything right though QT and a Naso died 2 days after introduced to DT with no clue why!!! It does stink

Aquarist76 · Dec 10, 2019

moz71 said:
I feel for you buddy!. I just finished a post where I did everything right though QT and a Naso died 2 days after introduced to DT with no clue why!!! It does stink

Yeah. In my case losing $1500 on fish that died w/n 24-36hrs with a seller that doesn't give refunds and the only thing I can think went wrong was the seller treating the fish with long-term Mardel in his setup and then using Mardel tainted water in the the transport bags. I think it made the fish not hearty enough to handle the ammonia build up during transfer. Usually sellers don't feed fish a day or two prior to transport to decrease poop/ammonia in the bags, and he feed them up to when I was there to pick them up. Knowing for a week before when I was going to be coming to get them.

rkpetersen · Dec 10, 2019

Did you happen to dip any of the corpses? I've had mysterious wipeouts in qt like this, and it turned out to be flukes.
Other possibilities might be pathologic bacteria in the tank, or some toxic element.
If your ammonia checker stayed pure yellow like that through the whole thing, it wasn't ammonia.
Probably be a good idea to reboot that QT.

Aquarist76 · Dec 11, 2019

The QT was literally a brand new set up (tank, filter, all equipment). Will definitely be tearing it down and cleaning everything. I didn't dip any of the dead fish but they were pristine.

My test fish has now been in that tank for over 48hrs and doing fine so I don't think it was anything about my set up, that's for sure.

Aquarist76 · Dec 11, 2019

Here's a couple of photos of two of the dead fish.

artieg1 · Dec 11, 2019

In my experience, fewer is better when adding fish in a QT. I don't trust the badges (I had several successive QT overcrowding wipeouts several years ago and the badge never changed color on me). Best change I've ever made to my QT protocol is to go with only 1-2 fish at a time, include tons of water movement, and seed heavily from biomedia in your DT. Oxygen deprivation could be another issue in a new sterile tank, with 4 very active fish put in it. Not completely letting the seller off the hook here, but the fact that a single dottyback is "doing fine" also supports the overcrowding theory. Tangs create a lot of waste.

Aquarist76 · Dec 11, 2019

artieg1 said:
In my experience, fewer is better when adding fish in a QT. I don't trust the badges (I had several successive QT overcrowding wipeouts several years ago and the badge never changed color on me). Best change I've ever made to my QT protocol is to go with only 1-2 fish at a time, include tons of water movement, and seed heavily from biomedia in your DT. Oxygen deprivation could be another issue in a new sterile tank, with 4 very active fish put in it. Not completely letting the seller off the hook here, but the fact that a single dottyback is "doing fine" also supports the overcrowding theory. Tangs create a lot of waste.

I did have an air bubbler and plenty of water movement and again tested ammonia via Red Sea kit and Ammonia test strip as well as the Alert badge and all came back normal. I can't say 100% it had to do with the seller, but the ammonia couldn't have spiked and gone away that quickly in a brand new tank with nothing to break it down. Definitely don't think it was an O2 problem either but I appreciate your thoughts.