Sudden clownfish death - help ID?

[Sonam]

Our two clownfish were acting completely normal last night. They ate normally and played in the current as usual.

Today when we got home we found this one. We haven't located the second one yet but it's missing from view. They are normally always visible.

We've dealt with maribe velvet before but this does not look like that at all. There seems to be dark areas of the body and the eyes are gone but snails were already eating it.

Any ideas? What can we do for the rest of the fish?

Tested water last week
SG 1.026
Nitrates 12
Calcium 430

Didn't do other tests.

 

[Big G]

To help we need a bit of information. Are these "new" fish? How long have you had them? Were any other "new" fish, inverts added to your tank recently? Do you QT your incoming fish & inverts?

 

[Sonam]

We've had these clowns for a few months. They went through quarantine when they arrived in late December.
We haven't added any new fish in over a month.
We got some new turbo snails last week. But otherwise tank parameters have been stable for a few months (we had an outbreak of marine velvet in October and left the main display fallow for two months).
But there two were totally normal last night. We have seen sick fish before. This was really sudden.

 

[Big G]

Were the new turbo snails QT'd?

 

[Big G]

Two things that can kill fish very rapidly are velvet and gram-negative bacterial infections.

Velvet tomonts can "encyst" on hard surfaces like snail shells, rock, glass, etc. and survive for up to 6 weeks without a fish host. So if there were velvet tomonts on the recently introduced snails. They hatch, find your clowns, attack them. And because of a clowns thicker slime coat, there can be little if no evidence on the surface of the fish, but the gills are attacked by overwhelming numbers of parasites. Velvet is rampant in the industry these days. And there have been some particularly nasty strains going around that kill really fast.
Here's Humblefish's complete treatment plan for velvet. What is of importance is his discovery that after doing a freshwater dip, you immediately give the fish a bath in acriflavine or Ruby Reef Rally and then treat with copper or CP. Apparently the survival rates increased dramatically with the acriflavine or Ruby Reef Rally bath. Here's the link. Hope this helps:
https://www.reef2reef.com/threads/velvet-amyloodinium-ocellatum.217570/#post-2499399

The other possibility is that perhaps some water with the gram-negative bacteria came in with those new snails. The treatment for what seems to be an apparently nasty gram-negative bacterial infection is the "trifecta" of Kanaplex + Furan2 + Metro for 10-14 days.
https://www.reef2reef.com/threads/bacterial-infections.191511/

 

[Humblefish]

Just to be sure about something... The white things I am seeing on the clownfish are debris/sand, correct?

 

[Sonam]

Just to be sure about something... The white things I am seeing on the clownfish are debris/sand, correct?

Yes. Sand. The fish was partly under a rock being eaten by a snail.

Thank you for the information. We installed a UV filter after the last episode but I do know that's not a complete protection but rather a management tool.

We did not qt the snails.

Sigh....

 

[Sonam]

Just to be sure about something... The white things I am seeing on the clownfish are debris/sand, correct?

The snails came from the same shop as the sick fish that gave us our outbreak of velvet in October. We had 5 years of stability up until then. He's a nice guy, the owner, has helped us a lot over the years. But this is a big problem. Thank you again.

 

[Humblefish]

The snails came from the same shop as the sick fish that gave us our outbreak of velvet in October. We had 5 years of stability up until then. He's a nice guy, the owner, has helped us a lot over the years. But this is a big problem. Thank you again.

I recommend setting up a coral/invert QT: https://www.reef2reef.com/ams/how-to-quarantine-coral-and-inverts.228/