All Fish death mystery

[dainS]

OK guys so back in December 2024 I started my first saltwater marine tank. I have been keeping freshwater fish pretty much for about seven years. This is my first jump into this. I did an insane amount of research to make sure I did it right all I wanted was 20 gallon tank soft corals clown fish that’s it nothing special. I Start up the tank. I did a fishless cycle. I had the tank set up for about three months before I added anything to it bought one clown fish passed away within a week so I decided to just let the tank cycle more figured there was some issue with ammonia or high nitrate nitrates something like that Let it sit and tell another month then I added a bunch of hermit crabs and snails those guys were thriving. Then move to a new home transferred everything to my new home. Let it sit for up for another few weeks Everything seemed to be thriving in there. I even have some corals growing macroalgae two mangroves all of my cleanup. Crew members are still doing great. Added a pair of clown fish two days later they died waited another few weeks had another pair of clown fish they died within 12 hours. My acclamation process was thorough with about a 45 minute acclamation process for the fish. I have no idea what is killing all of my fish Somewhere in between there. I also had a watchmen Gobi that lived in there for a couple weeks before he died. What is happening. My testing comes back normal. Nitrates are zero nitrates are zero ammonia is completely undetectable. My pH is between 8.2 and 8.4 my alkalinity hovers between six and seven. I’m considering some kind of poisoning may tear down scrub the tank and get new media sand and rock

 

[Jay Hemdal Verified Community Expert]

OK guys so back in December 2024 I started my first saltwater marine tank. I have been keeping freshwater fish pretty much for about seven years. This is my first jump into this. I did an insane amount of research to make sure I did it right all I wanted was 20 gallon tank soft corals clown fish that’s it nothing special. I Start up the tank. I did a fishless cycle. I had the tank set up for about three months before I added anything to it bought one clown fish passed away within a week so I decided to just let the tank cycle more figured there was some issue with ammonia or high nitrate nitrates something like that Let it sit and tell another month then I added a bunch of hermit crabs and snails those guys were thriving. Then move to a new home transferred everything to my new home. Let it sit for up for another few weeks Everything seemed to be thriving in there. I even have some corals growing macroalgae two mangroves all of my cleanup. Crew members are still doing great. Added a pair of clown fish two days later they died waited another few weeks had another pair of clown fish they died within 12 hours. My acclamation process was thorough with about a 45 minute acclamation process for the fish. I have no idea what is killing all of my fish Somewhere in between there. I also had a watchmen Gobi that lived in there for a couple weeks before he died. What is happening. My testing comes back normal. Nitrates are zero nitrates are zero ammonia is completely undetectable. My pH is between 8.2 and 8.4 my alkalinity hovers between six and seven. I’m considering some kind of poisoning may tear down scrub the tank and get new media sand and rock

Welcome to Reef2Reef!

Your fish losses may or may not be related to each other.

Are there invertebrates in the tank? Soft corals, etc.? If so and if they are doing well, then that points to fish disease or poor quality fish.

One thing that is pretty common is for stores to hold their fish at lower salinity and then they are severely stressed moving them into your tank - even careful acclimation doesn’t always work. Ask your dealer what their salinity is.

 

[Mr. Mojo Rising]

Did you test the salinity of your LFS water? Many LFS's keep low salinity, my LFS water tests at 1.017, in this case it takes a very long acclimation process. Just a possibility...

 

[jsmkmavity]

Were all the fish from the same place? I agree that low salinity at lfs can be a problem. Another possibility, how is your surface agitation? They might not be getting enough oxygen if the acclimation isnt the problem. Have you been having algae blooms?

 

[dainS]

Welcome to Reef2Reef!

Your fish losses may or may not be related to each other.

Are there invertebrates in the tank? Soft corals, etc.? If so and if they are doing well, then that points to fish disease or poor quality fish.

One thing that is pretty common is for stores to hold their fish at lower salinity and then they are severely stressed moving them into your tank - even careful acclimation doesn’t always work. Ask your dealer what their salinity is.

Yeah, I agree. The fish loss may not be. Related. Their behaviors did seem to be different.

Yes, there’s several and birds living in a tank. There’s 500 crabs and a number of necessary snails I also believe that the itty-bitty candy cane pistol shrimp I added a while back is still alive, although I never see him. I also have a small disc on a mushroom and a photosynthetic Oregonian that I’ve been living in there for a few weeks now and they both seem to be doing just fine.

I did check the salinity this time when I added these most recent pair and the salinity I believe was closer to 1.026 which surprised me I do keep my tank exactly 1.025. I also calibrate my reflectometer regularly.

Thank you so much for the replies really appreciate it

 

[dainS]

Did you test the salinity of your LFS water? Many LFS's keep low salinity, my LFS water tests at 1.017, in this case it takes a very long acclimation process. Just a possibility...

I did check the salinity this go around and I was surprised to see that the salinity was about 1.026 in the bag

 

[dainS]

Were all the fish from the same place? I agree that low salinity at lfs can be a problem. Another possibility, how is your surface agitation? They might not be getting enough oxygen if the acclimation isnt the problem. Have you been having algae blooms?

Every fish was from a different place. I did check the salinity in the bag and it was 1.026 I keep my tank at 1.025. I run a dual random flow generator with one of the nozzles pointed upward to increase agitation. Believe it’s considered high I go through about 4 gallons of ATO water a week because of the surface agitation In my 20 cube. No crazy algae blooms, but I do have a bunch of red macro algae growing in there. Flow is light in the tank. Not running the wave maker because it seemed like to much flow

Maybe my acclimation was bad

 

[BryanM]

500 crabs? Even 50 would be a lot.... that has to be a typo.

Anyway, forgive me in advance for this, but you sounded kind of willy nilly in your cycling process and testing parameters. Do you know what salinity, PH, ALK, Nitrate, Phosphate, Ammonia (hopefully none), Calc and Mag are?

Most of us would not see a fish die in a day and just wait a few more weeks to add another fish... Especially hardy fish like clowns.

 

[dainS]

500 crabs? Even 50 would be a lot.... that has to be a typo.

Anyway, forgive me in advance for this, but you sounded kind of willy nilly in your cycling process and testing parameters. Do you know what salinity, PH, ALK, Nitrate, Phosphate, Ammonia (hopefully none), Calc and Mag are?

Most of us would not see a fish die in a day and just wait a few more weeks to add another fish... Especially hardy fish like clowns.

My bad yes I have five small hermit crabs

Salinity is 1.025

My ammonia is undetectable or zero I was using a red sea test kit, as well as a ammonia, alert tag in the aquarium.

Nitrate was at zero tested with both a red sea test kit as well as a Saifirt test kit

Nitrate was zero also tested with red sea

pH was at 8.4 yesterday tested with a red sea test kit

KH is at 6-7dkh