Fish dying?

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c.dickens9

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Currently have bio balls, sponge and activated carbon in the HOB, started the tank with Liverock so that’s all the rock work. I tested 0 for ammonia the entire ordeal so if that’s what it is then not sure why it’s testing 0
This is interesting - and important to point out - many tanks can run just on flow and no filtration except live rock in the tank. The HOB is handy for putting in carbon, etc. I wanted to ask - when you move the fish from tank 1 to tank 2, how long does it take to improve (you kind of implied it was instant or near instant) - additionally if you put the fish back from tank 2 to tank 1 how long does it take to get worse (the fish)
Everytime I’ve moved a fish it’s been right before I turn the lights out and they’ve completely recovered and are eating by the morning
And when I moved them back to the problematic tank they’d be fine for a day then go down hill again, atm have all fish in th smaller tank and they’re all fine now
 
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c.dickens9

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The one thing is that Coral is less sensitive to ammonia than fish - It would be really great if you could check a full set of parameters. Additionally - curious do the fish gulp air at the surface (more than likely an Oxygen problem) or are just breathing fast. Did you QT your fish - and have you added anything new when you upgraded your tank that might have brought a disease in, Again - disease shouldn't resolve - as @Jay Hemdal said - with changing tanks. It sounds like some kind of 'toxic issue' that coral is less susceptible to.
Some went to the surface some didn’t but all seemed to be breathing erratically. Yeah I’ve tested nitrites and ammonia many times both read 0 so definitely confusing. Don’t think it’s disease because they all recover over night when moved to a tank I’ve had running longer and don’t think it’s oxygen because I’ve got two powerheads at the surface and a large air stone. The only “new” thing I’ve added was a tang but that was pretty much the week I upgraded the tank so not that recently. Did have to be a bit of a rushed change of tanks because I had a leak and had to get one as fast as possible.
 

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Post a full shot or two of your Tank. Do you have an Algae Problem and have added any type of treatment? Is the water a bit cloudy? When you changed Tanks what did you do about the sand?
 
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c.dickens9

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Sounds like ammonia to me. Years ago I killed a subadult Passer Angle. Cleaned a bunch of fuzzy algae off my rocks and glass and let the canister filter clean it up. Forgot to clean the canister filter and it turned into an ammonia factory. Even after a big water change the ammonia would jump right up again. Learned a valuable lesson and lost a beautiful fish in the process.

Does the HOB perform all your filtration (Mechanical, Chemical,Biological)? Maybe its just not up to the task - I would think its not enough for a 60 mixed. Have you cleaned the filter media lately? Maybe some or all of the bacteria were removed and your tank is going through a mini cycle. I believe its always best to have 2 or 3 types of biological filtration. Live rock, media, and even a prefilter (sponge, floss) will work part time.
20260202_175606_E7CD265F-3236-4C4F-AC14-C21B7B4C8D8F.png
Current parameters
 

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For the last week I’ve been dealing with my fish in my display tank just becoming extremely lethargic not eating and then laying on the ground. It’s a relatively new tank moved them from a 33 to a 60 about a month ago and they randomly are dropping like flies. Then when I move them into my 15 gallon cube that’s been running for a few months they fully recover and are fine but if I put them back in main tank they become lethargic don’t eat and are on the ground again. Also noticed my clown’s top fin is becoming translucent. Haven’t had any parameter swings and even changed my water a few days ago which throws me for a loop even more. I just run a HOB with media and activated carbon but any advice helps all my inverts and coral seem completely unaffected by whatever is happening.
20260131_185236_0EB4F6D1-6802-432F-9293-B270EEAB578A.png
I agree it may be oxygen in the lower levels of the tank but you may also have a bristleworm or several bothering the fish at night when the lights are off. Causing them stress and wearing them down. What is the temp of the water? 76 to 78 is good for clownfish. Good luck!
 

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Since you transferred everything into a larger tank, was the sand also transferred? I would also remove and inspect the scraper and the magnets. You probably want at some point to add more rock. Are the items in the back right shells? Hard to tell. Also, are you adding a additives like Bacteria or something for Algae control?
 
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c.dickens9

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Since you transferred everything into a larger tank, was the sand also transferred? I would also remove and inspect the scraper and the magnets. You probably want at some point to add more rock. Are the items in the back right shells? Hard to tell. Also, are you adding a additives like Bacteria or something for Algae control?
I did transfer some of the sand yes, and yeah have some shells that I took from the beach a while back but they’ve been there since June so doubt they’re an issue. Bleached for a few hours and left in the sun for days
 
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c.dickens9

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Since you transferred everything into a larger tank, was the sand also transferred? I would also remove and inspect the scraper and the magnets. You probably want at some point to add more rock. Are the items in the back right shells? Hard to tell. Also, are you adding a additives like Bacteria or something for Algae control?
I did transfer some of the sand yes, and yeah have some shells that I took from the beach a while back but they’ve been there since June so doubt they’re an issue. Bleached for a few hours and left in the sun for days
Algae control I have a good pod population, 10+ turbo snails, bumblebee snails, sand sifting stars, nassareus snails emerald crabs etc
 

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So no additives were added? I would suspect the sand. It seems to be a common problem when transferring to new Tanks. There are a lot of examples on this Forum where Members have had loses.
 

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Even though ammonia is registering as zero, shouldn't nitrite be zero in a fully cycled tank as well? The fact that some nitrite is showing up (even a small amount) makes me wonder if it could be going through a mini cycle again. Forgive me if you already mentioned this, but have you cleaned your filter media recently? Sometimes that will drop your beneficial bacteria population low enough to cause a miniature cycle.

Definitely following along as this is a bit of mystery...
 

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