Amphidinium vs coolia Dinos

taylormaximus · Jan 16, 2024

Hey guys, just got a microscope to ID what's been covering my sand. It's a clumpy rust coloured coating on just the sandbed (not rocks or glass), it seems to be photosynthetic, but it doesn't disapate at night. When you stir it up it kind of strings the sand grains together, but the sand directly below is white. They aren't too aggressive, but they return after about 2 days of stirring or syphoning the sand. I'll attach some pictures below of in the tank as well as a microscopic view.

I've also lost a fair number of my clean up crew recently, although I can't conclusively say it's from them eating this, but it does seem connected. I'm fairly certain it's a type of dinos, but more on that below.

Here it is on the sand, clumped up in a few areas from stirring it up.

Here it is in the microscope, the large masses are grains of sand, the orange circles are coating all the grains. There also looks like something there stringing all the grains together, not sure if that's the mucus layer or possibly some other symbiotic algae. But based on the picture and the symptoms, I think I've narrowed it down to either Amphidinium or Coolia dinoflagellates. So my question for the Dino experts is based on the symptoms and pictures, which does this look more like? And what differentiates the two strains? Or if I've misidentified it, what else could it be?

I can share more about the tank conditions if that helps ID it, but I'm mostly looking for a clear ID with this post, I can post on another day about how to control it once I know what it is. Thanks for the help!

Temperature: 78F
DKh: 10
Phosphate: 0.1
Nitrate: 0 (I have hair algae consuming it all so it's stuck at 0)

Aaron75 · Jan 16, 2024

Are you sure it's not just diatoms?

taylormaximus · Jan 16, 2024

Aaron75 said:
Are you sure it's not just diatoms?

Not from pictures I've seen under a microscope. Diatoms seem to have an irregular crystal like appearance, almost like shards of glass, whereas dinos are normally quite round and consistently shaped. It does present itself very similarly to diatoms on the sand, although also from what I've read certain strains of dinos can look almost indistinguishable to diatoms. Additionally I've tried controlling phosphate in my system which normally fuels diatoms, and it didn't have any effect on this particular issue.

Troylee · Jan 16, 2024

@taricha coukd help ya out..

taylormaximus · Jan 16, 2024

Troylee said:
@taricha coukd help ya out..

I hope so!

taricha · Jan 18, 2024

taylormaximus said:
I hope so!

I can rule out coolia by cell shape. I can't distinguish between amphidinium and prorocentrum from those pics. But prorocentrum seem to move less and are more toxic. So if I have to guess, that's what I'm guessing.

taylormaximus · Jan 30, 2024

taricha said:
I can rule out coolia by cell shape. I can't distinguish between amphidinium and prorocentrum from those pics. But prorocentrum seem to move less and are more toxic. So if I have to guess, that's what I'm guessing.

@taricha Can you tell the difference between amphidinium and prorocentrum by symptoms in the tank? For instance, in the microscope the ones adhered to the sand didn't appear to be moving at all, and they appeared very round, possibly even spherical. And in the tank itself they are restricted just to the sand bed, I haven't seen evidence of any on the rocks, and they don't recede much if at all at night. It also doesn't really slime up or bubble like some strains, although the sand grains do string together when disturbed. I have lost some inverts to it, but it was pretty slow, over a couple weeks rather than days, none of my coral or fish have been affected thankfully.

Does any of that information lend itself to one strain more than the other?

Dan_P · Feb 2, 2024

taylormaximus said:
Hey guys, just got a microscope to ID what's been covering my sand. It's a clumpy rust coloured coating on just the sandbed (not rocks or glass), it seems to be photosynthetic, but it doesn't disapate at night. When you stir it up it kind of strings the sand grains together, but the sand directly below is white. They aren't too aggressive, but they return after about 2 days of stirring or syphoning the sand. I'll attach some pictures below of in the tank as well as a microscopic view.

I've also lost a fair number of my clean up crew recently, although I can't conclusively say it's from them eating this, but it does seem connected. I'm fairly certain it's a type of dinos, but more on that below.

Here it is on the sand, clumped up in a few areas from stirring it up.

Here it is in the microscope, the large masses are grains of sand, the orange circles are coating all the grains. There also looks like something there stringing all the grains together, not sure if that's the mucus layer or possibly some other symbiotic algae. But based on the picture and the symptoms, I think I've narrowed it down to either Amphidinium or Coolia dinoflagellates. So my question for the Dino experts is based on the symptoms and pictures, which does this look more like? And what differentiates the two strains? Or if I've misidentified it, what else could it be?

I can share more about the tank conditions if that helps ID it, but I'm mostly looking for a clear ID with this post, I can post on another day about how to control it once I know what it is. Thanks for the help!

Temperature: 78F
DKh: 10
Phosphate: 0.1
Nitrate: 0 (I have hair algae consuming it all so it's stuck at 0)

I would take a-closer look at your rocks too. There are both bright green patches - can’t tell if algae or cyanobacteria - and there are brown stains on the rock surfaces I can see.

taylormaximus · Feb 3, 2024

Dan_P said:
I would take a-closer look at your rocks too. There are both bright green patches - can’t tell if algae or cyanobacteria - and there are brown stains on the rock surfaces I can see.

Yeah that's another issue I'm looking into, I believe it's green cyano on the rocks, I have microscope pictures of that as well, but I'll save that for another post, it's less concerning than the nonsense on the sand!