Bacterial bloom? Velvet? What killed my fish?

[Saralay]

Hi everyone,

My new tank is going through a bacterial bloom. It started a couple of weeks ago, but I set up a small UV and didn’t give it much importance, as I’ve had these before and they usually clear up with time. This time, however, it didn’t.

Two days ago, I noticed my fish acting strangely. A few hours later, some of them started dying. I managed to save 2 out of 7 by moving them to a different tank, I gave them a ruby rally pro bath and right now they seem to be ok. A royal gramma, a mandarin dragonet and a clownfish died and were taken out. However, a Banggai and a YWG went missing. I suspect they are dead somewhere in the rockwork, but I haven’t been able to find them.

I think the plausible cause is a lack of oxygen in the water caused by the bacterial bloom, but what really puzzles me is that none of the invertebrates seem to be affected. I have several corals, two skunk cleaner shrimp, a pistol shrimp, a serpent starfish, around 20 snails, and a couple of conchs, and all of them appear completely fine. There are also lots of pods on the glass too.

I’ve installed a stronger UV in the sump (55W), but the bacterial bloom is still going strong after 24 hours. It looks even worse in fact. I suspect it may be fueled by the missing fish corpses.

Could it be that invertebrates need much less oxygen than fish? I also wondered whether velvet might have found its way into my system along with the bacterial bloom, as I only do observational quarentine for 20 days, but aside from rapid breathing before dying, none of the fish showed any other symptoms.

I’m really at a loss. Some of those fish have been with me for a long time, and I’d hate for this to happen again if I add new ones.

 

[Jay Hemdal Verified Community Expert]

Hi everyone,

My new tank is going through a bacterial bloom. It started a couple of weeks ago, but I set up a small UV and didn’t give it much importance, as I’ve had these before and they usually clear up with time. This time, however, it didn’t.

Two days ago, I noticed my fish acting strangely. A few hours later, some of them started dying. I managed to save 2 out of 7 by moving them to a different tank, I gave them a ruby rally pro bath and right now they seem to be ok. A royal gramma, a mandarin dragonet and a clownfish died and were taken out. However, a Banggai and a YWG went missing. I suspect they are dead somewhere in the rockwork, but I haven’t been able to find them.

I think the plausible cause is a lack of oxygen in the water caused by the bacterial bloom, but what really puzzles me is that none of the invertebrates seem to be affected. I have several corals, two skunk cleaner shrimp, a pistol shrimp, a serpent starfish, around 20 snails, and a couple of conchs, and all of them appear completely fine. There are also lots of pods on the glass too.

I’ve installed a stronger UV in the sump (55W), but the bacterial bloom is still going strong after 24 hours. It looks even worse in fact. I suspect it may be fueled by the missing fish corpses.

Could it be that invertebrates need much less oxygen than fish? I also wondered whether velvet might have found its way into my system along with the bacterial bloom, as I only do observational quarentine for 20 days, but aside from rapid breathing before dying, none of the fish showed any other symptoms.

I’m really at a loss. Some of those fish have been with me for a long time, and I’d hate for this to happen again if I add new ones.

Shrimp have pretty high oxygen requirements. I would expect those to die if the O2 was really low.

Does the tank have air stones or a protein skimmer? Those both help with oxygenation better than water flow from pumps does.

Low oxygen shows up most at night. Finding fish dead in the morning, especially with their mouth open can be a sign.

 

[Saralay]

Shrimp have pretty high oxygen requirements. I would expect those to die if the O2 was really low.

Does the tank have air stones or a protein skimmer? Those both help with oxygenation better than water flow from pumps does.

Low oxygen shows up most at night. Finding fish dead in the morning, especially with their mouth open can be a sign.

It has a skimmer yeah. The fish started dying at night.

 

[vetteguy53081]

Hi everyone,

My new tank is going through a bacterial bloom. It started a couple of weeks ago, but I set up a small UV and didn’t give it much importance, as I’ve had these before and they usually clear up with time. This time, however, it didn’t.

Two days ago, I noticed my fish acting strangely. A few hours later, some of them started dying. I managed to save 2 out of 7 by moving them to a different tank, I gave them a ruby rally pro bath and right now they seem to be ok. A royal gramma, a mandarin dragonet and a clownfish died and were taken out. However, a Banggai and a YWG went missing. I suspect they are dead somewhere in the rockwork, but I haven’t been able to find them.

I think the plausible cause is a lack of oxygen in the water caused by the bacterial bloom, but what really puzzles me is that none of the invertebrates seem to be affected. I have several corals, two skunk cleaner shrimp, a pistol shrimp, a serpent starfish, around 20 snails, and a couple of conchs, and all of them appear completely fine. There are also lots of pods on the glass too.

I’ve installed a stronger UV in the sump (55W), but the bacterial bloom is still going strong after 24 hours. It looks even worse in fact. I suspect it may be fueled by the missing fish corpses.

Could it be that invertebrates need much less oxygen than fish? I also wondered whether velvet might have found its way into my system along with the bacterial bloom, as I only do observational quarentine for 20 days, but aside from rapid breathing before dying, none of the fish showed any other symptoms.

I’m really at a loss. Some of those fish have been with me for a long time, and I’d hate for this to happen again if I add new ones.

Please post a video under bright white light, no blue and of at least 20 seconds.
Were fish found dead with mouth open?
Were they breathing heavy?
UV will address an algae bloom in lieu of bacterial which happens (if bacterial) when bacterial colonies suddenly increase in number, they become suspended in the water and grow quickly and become more visible causing the water to be milky and hazy in appearance due to nutrient increases in the water with nitrates and phosphates, so check those two. Can also be poor filtration, not movement, overfeeding and even your water source especially if RODI filters are nearing end of useful life.
If the bacteria does not get enough oxygen, this issue begins
When fish are dying and inverts doing well, often it will be due to disease in lieu of water quality issue

 

[Saralay]

Please post a video under bright white light, no blue and of at least 20 seconds.
Were fish found dead with mouth open?
Were they breathing heavy?
UV will address an algae bloom in lieu of bacterial which happens (if bacterial) when bacterial colonies suddenly increase in number, they become suspended in the water and grow quickly and become more visible causing the water to be milky and hazy in appearance due to nutrient increases in the water with nitrates and phosphates, so check those two. Can also be poor filtration, not movement, overfeeding and even your water source especially if RODI filters are nearing end of useful life.
If the bacteria does not get enough oxygen, this issue begins
When fish are dying and inverts doing well, often it will be due to disease in lieu of water quality issue

-I didn't check if the mouth was open but they had heavy breathing before dying. That was the only sympton.
-Nitrates and phosphates were really low, in fact I had trouble keeping them above 0 to the point that I started adding bottled nitrate and phosphate to prevent dinos. Last values were 0.3 for nitrate and 0.04 phosphate before the fish dying.
-The water is milky and hazy. It really looks like a bacterial bloom.
-The RODI filters are new.
-The tank is a 250 gallon with around 80 kilograms of rock, around 30 kilos is very mature rock from my previous tank. I don't think filtration was the issue as there were only 7 small fish in there, and the fish have been in this new tank for a couple months without trouble before this started.

 

[vetteguy53081]

-I didn't check if the mouth was open but they had heavy breathing before dying. That was the only sympton.
-Nitrates and phosphates were really low, in fact I had trouble keeping them above 0 to the point that I started adding bottled nitrate and phosphate to prevent dinos. Last values were 0.3 for nitrate and 0.04 phosphate before the fish dying.
-The water is milky and hazy. It really looks like a bacterial bloom.
-The RODI filters are new.
-The tank is a 250 gallon with around 80 kilograms of rock, around 30 kilos is very mature rock from my previous tank. I don't think filtration was the issue as there were only 7 small fish in there, and the fish have been in this new tank for a couple months without trouble before this started.

Please again post pic or video of tank and how are you testing levels?
The chemicals added may or may have not played a role but the numbers posted are/were acceptable.

 

[Saralay]

The remaining fish died in the new holding tank, but not a single invert is affected in the DT, So I guess It is safe to say that this was velvet.

Observational quarentine had worked for me until now, but live and learn I guess. I'll do a full profilactic quarentine from now on.