Rapid goby death with unknown cause (...prazi?)

[eag]

Hello. My goby died today right in front of me, and all I want to know is why. It happened really fast - less than 30 minutes. Everything in the tank, including four other fish, look fine. Even the dead goby looks fine, apart from it being dead. I'll try my best to organize the information in a way that makes it easier to read.

The tank is around 35 gallons.

The Death
I was on an important conference call today and noticed my yellow watchman goby pop out of its hole and perch in an unusual way. Kind of on its side. It was still moving around and watching out for its pistol shrimp friend, but it wasn't looking right in its movement and the way it stopped and settled.

I observed it, and saw that its breathing rate was normal, if anything it may have been slow. Slow normal. He began to move around the tank and lay at an angle in spots that he normally doesn't visit. At this time, it was very clear that it was in distress.

Finally, he settled in a corner of the tank, and stopped breathing. It's been less than 30 minutes since this story began.

An ORP probe measured a sudden drop in potential right around the time the fish stopped breathing. Nassarius snails activated extremely quickly. Big ones, ones I didn't know I had. I removed the fish from the tank as soon as I could, and shook two snails off of it. 30 minutes have gone by since the time the fish settled in the corner and now.

After the Death
When I pulled the fish out, it looked normal to me. It had a fat belly... but I just assumed that he was well fed. I photographed both sides. I could not see any problem, injury etc. At one point, I noticed a light red spot on the paper towel it was on, which looked like it could be blood. It was a small spot, it may have come from the head/mouth area of the fish.

For the next 30 minutes, nassarius snails swamp the spot the fish died on and roam around the region.

Before the Death
This fish has been in the tank for a little over a year. It had a well established territory, and has been bonded with a pistol shrimp since the first few days of its arrival.

All fish in the tank (including the goby, three fish) had gill flukes. I put the display under PraziPro treatment. Since I don't have a QT, I decided that the best time to introduce new fish is during the PraziPro treatment cycle. After two PraziPro treatments (and associated water changes), I introduced new livestock (two small fish, some coral) and a third round of PraziPro at the same time. All rounds were 6-7 days apart with ~25% WCs in between.

The night that this was performed, I noticed the goby acting a little unusual. It was in a weird spot and laying in a weird way, and letting the cleaner shrimp pick on it. I brushed it off as getting a cleaning. I didn't notice anything unusual beyond that until the incident occurred.

What Happened?
I'm worried for the rest of the fish. I want to know if I made an error. An ammonia badge in the sump did not show a reading, and an API ammonia test also did not show a reading. So I don't think it's that.

If it was something about the water changes, the other fish should have been affected, even just a little bit? Everything looks normal.

I've only ever heard of wrasses being sensitive to Prazi ... but is it possible that this goby was too? The unusual behavior I witness the night before the death wasn't long after the third dose of PraziPro was administered.

What the heck happened??

 

[MnFish1]

Reading this is a little confusing as to exactly 'what' you did. It sounds like you MIGHT be relating things that are unrelated to the problem?

1. Just because the goby 'popped out' and looked a little weird, doesn't mean that he wasn't sick for a much longer period (i.e. hours) - in other words it might not have been as sudden an illness as you're thinking?
2. The ORP drop - how much was 'the drop'. The only thing I can think of (and I doubt it) is that the gobie hit a pocket of Hydrogen sulfide under the sand/rock and thus the ORP drop. Did it come back up again? The second thing would be that the ORP dropped when you took out the fish - or the ORP is a non-issue.
3. Some of the wording you're using isn't clear (to me) - ie. its unclear exactly how much prazipro was added, and exactly 'when' as compared to the 'death'. Reading what you wrote, makes it sound like you added 3 doses of prazipro - without making water changes? Even though lets say you have 6 fish in the tank - maybe only one might be affected by an overdose.
4. You added some new fish - I assume without QT. This could have caused a new disease outbreak in your tank - velvet, etc etc. Prazipro would not treat many of these parasites.
5. You mention the 'blood spot' - this could have been an early sign of a bacteria or other infection - which might have been brewing, and you did not see so I guess that could be another option (i.e. from an injury?)

Please don't take any of this as a criticism - thanks for all the information you provided - which is a big help trying to figure it out. I'm sure others will weigh in - sorry for the loss of your fish!!

 

[Jay Hemdal]

Hello. My goby died today right in front of me, and all I want to know is why. It happened really fast - less than 30 minutes. Everything in the tank, including four other fish, look fine. Even the dead goby looks fine, apart from it being dead. I'll try my best to organize the information in a way that makes it easier to read.

The tank is around 35 gallons.

The Death
I was on an important conference call today and noticed my yellow watchman goby pop out of its hole and perch in an unusual way. Kind of on its side. It was still moving around and watching out for its pistol shrimp friend, but it wasn't looking right in its movement and the way it stopped and settled.

I observed it, and saw that its breathing rate was normal, if anything it may have been slow. Slow normal. He began to move around the tank and lay at an angle in spots that he normally doesn't visit. At this time, it was very clear that it was in distress.

Finally, he settled in a corner of the tank, and stopped breathing. It's been less than 30 minutes since this story began.

An ORP probe measured a sudden drop in potential right around the time the fish stopped breathing. Nassarius snails activated extremely quickly. Big ones, ones I didn't know I had. I removed the fish from the tank as soon as I could, and shook two snails off of it. 30 minutes have gone by since the time the fish settled in the corner and now.

After the Death
When I pulled the fish out, it looked normal to me. It had a fat belly... but I just assumed that he was well fed. I photographed both sides. I could not see any problem, injury etc. At one point, I noticed a light red spot on the paper towel it was on, which looked like it could be blood. It was a small spot, it may have come from the head/mouth area of the fish.

For the next 30 minutes, nassarius snails swamp the spot the fish died on and roam around the region.

Before the Death
This fish has been in the tank for a little over a year. It had a well established territory, and has been bonded with a pistol shrimp since the first few days of its arrival.

All fish in the tank (including the goby, three fish) had gill flukes. I put the display under PraziPro treatment. Since I don't have a QT, I decided that the best time to introduce new fish is during the PraziPro treatment cycle. After two PraziPro treatments (and associated water changes), I introduced new livestock (two small fish, some coral) and a third round of PraziPro at the same time. All rounds were 6-7 days apart with ~25% WCs in between.

The night that this was performed, I noticed the goby acting a little unusual. It was in a weird spot and laying in a weird way, and letting the cleaner shrimp pick on it. I brushed it off as getting a cleaning. I didn't notice anything unusual beyond that until the incident occurred.

What Happened?
I'm worried for the rest of the fish. I want to know if I made an error. An ammonia badge in the sump did not show a reading, and an API ammonia test also did not show a reading. So I don't think it's that.

If it was something about the water changes, the other fish should have been affected, even just a little bit? Everything looks normal.

I've only ever heard of wrasses being sensitive to Prazi ... but is it possible that this goby was too? The unusual behavior I witness the night before the death wasn't long after the third dose of PraziPro was administered.

What the heck happened??

How did you confirm that the fish had gill flukes?
Did you happen to lift a gill cover and look at the goby's gills after it died?

Here is what I can tell you so far: the drop in ORP corresponds with a drop in dissolved oxygen. That in turn is a result of bacterial degradation of the solvent used in Prazipro (Oxybispropanol - a glycol). You need to increase aeration (not just flow) in tanks when dosing Prazipro. It is rare, but not unheard of, for fish to die due to the low dissolved oxygen event.

As second, more common event is this: if the fish had a severe gill flukes infestation, think of each fluke attached to a gill lamellae, sucking blood. However, they act like little corks. When knocked off the fish by Prazi, that leaves hundreds/thousands of little holes in the gills and the fish bleeds out. However, that is more common after the first prazi treatment, not the second or third. I've experimented with giving fish a short FW dip to knock of a percentage of the flukes, then let them heal a few days and then dose them, but timing on that is all just a guess.

Finally, there are a few, undetectable issues that can cause random fish deaths (aneurysms, fatty liver, etc.) - and then cause and effect can become murky.


Jay

 

[eag]

Thanks so much everyone for your responses

Reading this is a little confusing as to exactly 'what' you did. It sounds like you MIGHT be relating things that are unrelated to the problem?

Sorry, I didn't mean to suggest that everything is related. There were a few things going on at the time and it felt important to document them.

1. Just because the goby 'popped out' and looked a little weird, doesn't mean that he wasn't sick for a much longer period (i.e. hours) - in other words it might not have been as sudden an illness as you're thinking?

That's fair, I suppose he could have been distressed under the rocks previously. I was watching the tank all day, and when he came out that one time I knew something was wrong... he died around 20-30 minutes later but was already a goner by just 5 minutes into that episode.

2. The ORP drop - how much was 'the drop'. The only thing I can think of (and I doubt it) is that the gobie hit a pocket of Hydrogen sulfide under the sand/rock and thus the ORP drop. Did it come back up again? The second thing would be that the ORP dropped when you took out the fish - or the ORP is a non-issue.

440 to 427. Yes it bounced back, but that might have been after I removed the fish. I observed the ORP drop prior to removing the fish.

Here is what I can tell you so far: the drop in ORP corresponds with a drop in dissolved oxygen. That in turn is a result of bacterial degradation of the solvent used in Prazipro (Oxybispropanol - a glycol). You need to increase aeration (not just flow) in tanks when dosing Prazipro. It is rare, but not unheard of, for fish to die due to the low dissolved oxygen event.

I was measuring dissolved oxygen during this whole thing. It measured 83 percent when the fish died. I am running an airstone as well. The other fish seemed ok, and I think if the oxygen was too low then the fish would have been breathing more rapidly or heavily?

3. Some of the wording you're using isn't clear (to me) - ie. its unclear exactly how much prazipro was added, and exactly 'when' as compared to the 'death'. Reading what you wrote, makes it sound like you added 3 doses of prazipro - without making water changes? Even though lets say you have 6 fish in the tank - maybe only one might be affected by an overdose.

This was the third dose of PraziPro. 6-7 days after every dose, I performed a ~25% water change and dosed again. Each dose was two teaspoons, it's a 42 gallon system.

4. You added some new fish - I assume without QT. This could have caused a new disease outbreak in your tank - velvet, etc etc. Prazipro would not treat many of these parasites.

It could be possible, but everyone else is still doing fine and looking fine. Could something goby-specific have been introduced?

Please don't take any of this as a criticism

Of course not thank you for the help!

How did you confirm that the fish had gill flukes?

I believe all fish in the tank had gill flukes, some severely. I saw behavior like yawning, flashing (specifically in the gill area), darting, stovepiping. The fish that died, I observed several times rubbing its gills into the sand in flashing-like behavior. I did a FW dip on one, much of this is documented here: https://www.reef2reef.com/threads/gill-flukes-but-not-gill-flukes.819671/

Did you happen to lift a gill cover and look at the goby's gills after it died?

Shoot I did not... I knew I should have done something more when I looked at it... Oh well

As second, more common event is this: if the fish had a severe gill flukes infestation, think of each fluke attached to a gill lamellae, sucking blood. However, they act like little corks. When knocked off the fish by Prazi, that leaves hundreds/thousands of little holes in the gills and the fish bleeds out. However, that is more common after the first prazi treatment, not the second or third.

Yes, that could make sense... and could also be the red spot on the paper towel? But yea I also would think it would have happened earlier. As mentioned, this was the third round.

Finally, there are a few, undetectable issues that can cause random fish deaths (aneurysms, fatty liver, etc.) - and then cause and effect can become murky.

Ugh yes... I hate that it could be something like this and I'll never know if it was something I did or not.

Thanks again everyone, this is really helpful

 

[eag]

Oh on the ORP thing... I thought to look at ORP after I saw the nassarius snails going crazy. I had read that ORP can be hit after a death, and I assume something must have been in the water to set the snails off. So I checked ORP thinking maybe the fish finally died, ORP had experienced this step function, at which point I declared the fish dead and removed it

 

[MnFish1]

Thanks so much everyone for your responses



Sorry, I didn't mean to suggest that everything is related. There were a few things going on at the time and it felt important to document them.



That's fair, I suppose he could have been distressed under the rocks previously. I was watching the tank all day, and when he came out that one time I knew something was wrong... he died around 20-30 minutes later but was already a goner by just 5 minutes into that episode.



440 to 427. Yes it bounced back, but that might have been after I removed the fish. I observed the ORP drop prior to removing the fish.



I was measuring dissolved oxygen during this whole thing. It measured 83 percent when the fish died. I am running an airstone as well. The other fish seemed ok, and I think if the oxygen was too low then the fish would have been breathing more rapidly or heavily?



This was the third dose of PraziPro. 6-7 days after every dose, I performed a ~25% water change and dosed again. Each dose was two teaspoons, it's a 42 gallon system.



It could be possible, but everyone else is still doing fine and looking fine. Could something goby-specific have been introduced?



Of course not thank you for the help!



I believe all fish in the tank had gill flukes, some severely. I saw behavior like yawning, flashing (specifically in the gill area), darting, stovepiping. The fish that died, I observed several times rubbing its gills into the sand in flashing-like behavior. I did a FW dip on one, much of this is documented here: https://www.reef2reef.com/threads/gill-flukes-but-not-gill-flukes.819671/



Shoot I did not... I knew I should have done something more when I looked at it... Oh well



Yes, that could make sense... and could also be the red spot on the paper towel? But yea I also would think it would have happened earlier. As mentioned, this was the third round.



Ugh yes... I hate that it could be something like this and I'll never know if it was something I did or not.

Thanks again everyone, this is really helpful

Thansk for the extra info. My guess is that a 'drop' from 440 to 427 could easily relate to you putting your hand in the tank especially if it rapidly corrected. When I have seen ORP drops its like 400 to 200 or something like that (until whatever caused the drop to end)

EDIT - just saw your post about the ORP dropping and then putting your hand in

 

[eag]

I suppose another possibility like @MnFish1 suggested is that the pistol shrimp got it, and there was head trauma or something like that... which could also explain the spot of blood.

 

[eag]

Hey everyone, just wanted to give a quick update.

After some time and reflection, looking back at the timeline etc and with everything I learned from this thread... I think the only possible explanations are that the Goby died from injury or from the flukes as @Jay Hemdal suggested.

Considering that the Goby had been living with the pistol shrimp peacefully for over a year, I think aggression there is unlikely. I don't think there's anything else in the tank that could have done it to him.

One of the fish I introduced at that time has since gone missing. I saw it swimming in the water column for the first few days, then disappeared. Since it was a new arrival, and everyone else in the tank seems fine, I think it's probably unrelated...

So I'm currently of the opinion that the most likely cause of death, of the two possible options we identified, is bleeding out following prazi dose. Blood in the water could have been the source of the ORP drop as well as the mechanism that triggered the nassarius snails all at once. Blood on the napkin, and the relatively tight time correlation with the prazi dose, make this feel likely.

 

[Jay Hemdal]

Duplicate

 

[Jay Hemdal]

The only thing I would question is the ORP drop due to blood in the water- I see drops in ORP after feeding a tank, but I wonder if a small amount of blood would do the same?
Jay