Please Help, my fish die overnight.

[Warpigdave]

I have a 90 gallon with a 40 gallon sump. All my parameters are good excep alk at 12. My alk only got that high recently. The last 3 water changes I used different salt. But started using my old salt. I double check my results and calibrate my refractometer before use.
Anyways every time I've added new fish they look fine are eating fine then one morning about a week or 2 later they are dead. I always see them eating the day before but find them dead the following morning. It has really only happened on newer fish. I haven't seen much aggression towards the newer fish, a bit of chasing here and there. But I had 2 clowns die that weren't newer. I thought my tang was picking on the new fish so I isolated it, but I have another fish that died (large starry blenny) without the tang present. Not sure if we stressed out the blenny and it died because we were in the tank catching the tang. But he was out after that and eating.

So far newer fish that died, in this order. Squirrel Fish, 2 stripe Damsel, Allens Damsel, 2 Clownfish that have been in there for 2 months doing fine, and starry blenny.

I'm not sure if my water temps drop at night (the tank is in my basement) and my heater in the sump can't keep up. Maybe my heater is going bad but it's only 4 months old. I have kinda felt what seems like the water was maybe colder than it seems at other times (just by feel), but the temp on thermometer seems ok. And why would this only happen to newer fish?

 

[Lavey29]

What is your water temp and salinity? Do the fish ever show any signs of stress like gasping for air or heavy breathing? Do you QT the fish prior to adding them to the DT?

 

[i cant think]

I have a 90 gallon with a 40 gallon sump. All my parameters are good excep alk at 12. My alk only got that high recently. The last 3 water changes I used different salt. But started using my old salt. I double check my results and calibrate my refractometer before use.
Anyways every time I've added new fish they look fine are eating fine then one morning about a week or 2 later they are dead. I always see them eating the day before but find them dead the following morning. It has really only happened on newer fish. I haven't seen much aggression towards the newer fish, a bit of chasing here and there. But I had 2 clowns die that weren't newer. I thought my tang was picking on the new fish so I isolated it, but I have another fish that died (large starry blenny) without the tang present. Not sure if we stressed out the blenny and it died because we were in the tank catching the tang. But he was out after that and eating.

So far newer fish that died, in this order. Squirrel Fish, 2 stripe Damsel, Allens Damsel, 2 Clownfish that have been in there for 2 months doing fine, and starry blenny.

I'm not sure if my water temps drop at night (the tank is in my basement) and my heater in the sump can't keep up. Maybe my heater is going bad but it's only 4 months old. I have kinda felt what seems like the water was maybe colder than it seems at other times (just by feel), but the temp on thermometer seems ok. And why would this only happen to newer fish?

Check ammonia, nitrites and nitrates

 

[Warpigdave]

What is your water temp and salinity? Do the fish ever show any signs of stress like gasping for air or heavy breathing? Do you QT the fish prior to adding them to the DT?

Water temp hovers between 76-78, salinity 1.025. NO sign of gasping. I do not qt. I never have. but don't see why that would kill new fish only. Only thing I have changed is my skimmer, which works a lot better. And started adding copepods to my refugium.

 

[Warpigdave]

Check ammonia, nitrites and nitrates

I did 3 times. all are nearly 0. Also the weather here has gotten colder, so I was wondering if maybe the heater )it's in the sump, just can't keep up. It's a 200w eheim.

Another thing I thought of, if the water does get cooler at night and the heater can't keep up, I do notice my older fish all sleep together under a rock. maybe that helps them survive.

 

[i cant think]

Any sign of illness once the fish have died or entered the tank?

 

[Tim McLellan]

Do you have a controller for your heater? That will show any temperature fluctuations.

 

[Warpigdave]

Any sign of illness once the fish have died or entered the tank?

No signs of illness whatsever. All eat really well and are active.

 

[Warpigdave]

Do you have a controller for your heater? That will show any temperature fluctuations.

I do not

 

[BroccoliFarmer]

My first thought would be to oxygen levels. at night is when you stop having photo period. Are you running a protein skimmer? Do you have macroalgea with a reverse lighting schedule?

 

[i cant think]

Is there any definite aggression? Or even any stress signs in the tank?

 

[Tim McLellan]

I do not

You really should get one. Not just to show the temperature variations, but to warn you if/when your heater malfunctions, which eventually it is guaranteed to do. It's a disaster waiting to happen if you don't.

 

[Warpigdave]

My first thought would be to oxygen levels. at night is when you stop having photo period. Are you running a protein skimmer? Do you have macroalgea with a reverse lighting schedule?

I have a reef octopus 152s skimmer. I also use filter socks that I clean regularly. I do not have micro algae yet, but do have a light on my regium for copepods that runs the same time as my tank light. Chaeto is coming soon. But I just introduced that light 3 days ago, and the copepods about 1 week ago. The squirrel fish and allens damsel died before those additions.

 

[BroccoliFarmer]

I have a reef octopus 152s skimmer. I also use filter socks that I clean regularly. I do not have micro algae yet, but do have a light on my regium for copepods that runs the same time as my tank light. Chaeto is coming soon. But I just introduced that light 3 days ago, and the copepods about 1 week ago. The squirrel fish and allens damsel died before those additions.

Well..if you have a reef octopus skimmer and you are running it constantly, then I doubt oxygenation is your problem as the skimmer will give you plenty of gas exchange. You can take that one off your list then.

 

[Warpigdave]

Is there any definite aggression? Or even any stress signs in the tank?

There was a slight bit of aggression with my tomini tang and the new fish. He never bothered the clowns though, and barely bothered the starry blenny. He chased the squirrel fish a bit, and the 2 stripe damsel. My starry blenny died this morning but was eating last night after we removed the tang.

 

[i cant think]

There was a slight bit of aggression with my tomini tang and the new fish. He never bothered the clowns though, and barely bothered the starry blenny. He chased the squirrel fish a bit, and the 2 stripe damsel. My starry blenny died this morning but was eating last night after we removed the tang.

Have you double checked nitrate and nitrites? Anything - Even a dead fish - can cause a small ammonia cycle. Also high phosphate can harm a fish easily.

Another thing:
Did the person/LFS you get these fish from dose copper and keep it in track? These fish could’ve gotten copper burns in the gills if the copper wasn’t kept in track. I meant this for the newer fish instead of the older fish.

 

[Warpigdave]

Have you double checked nitrate and nitrites? Anything - Even a dead fish - can cause a small ammonia cycle. Also high phosphate can harm a fish easily.

Another thing:
Did the person/LFS you get these fish from dose copper and keep it in track? These fish could’ve gotten copper burns in the gills if the copper wasn’t kept in track. I meant this for the newer fish instead of the older fish.

I will check the nitrites and trates again, but this will be my 4th check. I have a very good cleanup crew that generally gets to the dead fish before I notice them, I've only seen the dead fish by my cuc on it. And then I remove it. This morning I saw my starry blenny laying only the bottom swimming oddly them it was dead so I reoved it immediately. I trust the store I buy them from, my friends work there. They do dose copper.

 

[ShakerBreaker]

Ok, there is a lot to unpack here.

You have been getting new fish, acclimating them (I'm assuming), then adding them directly to the display. These fish have all died within 1-2 weeks of adding them. Were these fish all bought at the same store? How much time between adding them or were they all added at once?


What are your current parameters?

Salinity, PH, Ammonia, Nitrate, etc?

Are you using RODI water or tap water?

You said your alkalinity was up to 12 just from water changes and a new salt? What salt did this? What salt did you switch back to?

I'm going to start off by saying check your PH immediately. if the salt brought your alkalinity to 12, it's possible there was a correlation to bringing your ph up as well.

 

[Warpigdave]

Ok, there is a lot to unpack here.

You have been getting new fish, acclimating them (I'm assuming), then adding them directly to the display. These fish have all died within 1-2 weeks of adding them. Were these fish all bought at the same store? How much time between adding them or were they all added at once?


What are your current parameters?

Salinity, PH, Ammonia, Nitrate, etc?

Are you using RODI water or tap water?

You said your alkalinity was up to 12 just from water changes and a new salt? What salt did this? What salt did you switch back to?

I'm going to start off by saying check your PH immediately. if the salt brought your alkalinity to 12, it's possible there was a correlation to bringing your ph up as well.

RODI Water, Instant Ocean originally. Then I got a really good deal on Reef Crsystals so switched to that. After a week I noticed my alk was higher so reduced drastically the amount of reef crystals and used more of the regular instant ocean. All the fish were bought from the same store. The squirrel fish and allini damsel bought together, about 2 weeks later the 2 stripe damsel and starry blenny. The clownfish were bought months before.

Salinity is 1.025
Ammonia near 0,
Nitrate and Nitrites near 0
Phosphates near 0, maybe a tad above.
PH about 12.2, it;s always been about 12.1/12.2.
Calc. about 380

I did run some gfo and carbon for a couple weeks but after my first couple fish died I stopped and decided I didn't need to. Especially after checking my po4.

 

[Warpigdave]

RODI Water, Instant Ocean originally. Then I got a really good deal on Reef Crsystals so switched to that. After a week I noticed my alk was higher so reduced drastically the amount of reef crystals and used more of the regular instant ocean. All the fish were bought from the same store. The squirrel fish and allini damsel bought together, about 2 weeks later the 2 stripe damsel and starry blenny. The clownfish were bought months before.

Salinity is 1.025
Ammonia near 0,
Nitrate and Nitrites near 0
Phosphates near 0, maybe a tad above.
PH about 12.2, it;s always been about 12.1/12.2.
Calc. about 380

I did run some gfo and carbon for a couple weeks but after my first couple fish died I stopped and decided I didn't need to. Especially after checking my po4.