Help me solve a mystery - kinda long!

Ok this is long, but please read it. I really need help!

Last night, disaster struck my tank and I can't figure out what happened. It is my new 40 gallon breeder tank, that I moved everyone into after my 37 started leaking. I moved the water and rock from the old tank, did not disturb the old sand, and put in 40 pounds of new sand and 15 gallons of freshly made water. I also used the same filter media.

My four fish were fine for 2 days. Then out of nowhere I notice my firefish start gasping. That fish was always stressed out and skiddish, so I didn't think much of it. Until I noticed my damsel gasping, then my clown started gasping. My psuedo never came out of the rocks. This happened in a matter of minutes.

The clown was hanging at the top of the water, gasping. Firefish and damsel were laying on the sand gasping.

My immediate thought was low oxygen. Even though it shouldn't be, the symptoms made me think that. So I made sure everything was off the top of the tank, and turned the powerhead so it was blasting the surface of the water.

I tested all params, and everything was spot on.

Half hour later or so - gasping still going on. By this point my damsel and firefish cannot even move and are just laying on the sand. My clown is still at the top of the water, but lifeless, hanging straight up and down and spinning in circles (probably from the current).

Then the firefish starts frantic shooting up and leaping out of the tank. When I noticed this happening, I threw a lid on. The firefish continued to frantically throw itself out of the water. Then exhausted crashed down onto the sand.

I had no idea what to do. I did all I could and turned the light off. I couldn't bear to watch. I was sick to my stomach.

When my fiance got home, about an hour or so later, everyone was dead, except my clown. Who I totally expected to be, the way he was acting.

My fiance removed the other three bodies. And by this point my clown is acting totally normal. Swimming around like normal, breathing like normal, etc. He even ate.

These fish were very healthy. I've had them over two years, and I'm very sad. My damsel was my first saltwater fish.

Ok, so what the heck happened!?!? I'm just at a total loss. The fish went from fine, to gasping, to dead in like 2 hours. No visual symptoms on fish. And now my clown is acting like nothing ever happened.

 

Kacy so sorry for your loss. I know how attached you are to your animals.

The gasping sounds like oxygen problem and the jumping sounds like electricity.

I see from your photos you had two heaters. Have you checked them for cracks? They may have gotten cracked from the move.

Did you rinse the sand in tap water before adding to the new tank? If so, how long from the time you rinsed the sand until the fish were added? If chlorine was present in the sand, it may have burned the fish gills and took a couple of days to present a problem.

How long was fresh saltwater mixed before adding to the tank with fish? Fresh mixed saltwater can also burn gills.

 

^^All great things to think about. My first thought was stray voltage.

 

I would have to agree to look at the heater, same thing happened to me. I had a "stealth heater" which cracked, leaked all the contents into the refugium and then into the tank causing the clown fish (the only inhabitant at the time, luckly) to start swimming in circles and become listless. I did a 20% water change, left all the lights off for a day and increased the oxygen in the tank with powerheads, after I took out that infernal heater and threw it away! The clown fish pulles through it, those are some tough fish! So sorry for your loss.

 

I agree, stray voltage could easily be the issue. You may not have even bumped a heater, but it is a possibilty. get a voltmeter and see what happens.

 

If you check with a voltmeter, make sure the heater thermostat is really ON when you make a measurement. Checked one once and all was good until the little red light came on then BAM.

 

So sorry for your loss, I've been there and it sucks. I agree on the stray voltage. When the other tank sprang a leak was the heater ever exposed out of the water (and still plugged in)? If I remember right this tank was sumpless?

 

I only have one heater in there now. I had two in there when the tank was not quite filled up, but only one was turned on (the one with lower wattage). And now there is just one heater on. I don't see any cracks in it and the temperature in the tank is staying stable.

I didn't rinse the sand, because I was worried about chlorine and I didn't want to waste all that RO water (takes so bloody long to make). But the fish were fine for two days! So seems like if it was the sand, it would have hit sooner?

I mixed the saltwater for about 24 hours before I added it to the tank.

I have a voltmeter, I'll figure out how to use it.

But if it was stray voltage, wouldn't my clown still be acting up? And can stray voltage cause low oxygen?

Feel free to ask more questions! I really am stumped with this one.

 

Yes, this tank is sumpless. The heater was never exposed out of the water in the leaking tank.

 

Set dial at 50V. Should be in the red section. Put the black prong in the ground of an outlet. Put the red one in your tank.