Hi all, new here and posting for the first time.
I have a 20-gallon IM Nuvo. It’s cycled and been running for almost 4 months. I slowly have been adding corals and snails.
I decided to get my first fish (2 weeks ago) (after much consideration) and started with a Royal Gramma. It was smaller and an LFS. The gramma seemed to be doing ok, it would come out during feeding and sometimes as the lights dimmed. Yesterday I did see her hanging out in her usual cave but it is toward the back of the tank so I can’t really see her too well.
This morning I went to feed and I he Gramma was no where to be found. I killed the filters to look from the top down and found her (in her usual corner) but not moving much. I waved some water in her direction and she shot up to the surface and got sucked to the filter grate.
I immediately put her in a separate container with water from the tank and spun up the heater on some fresh saltwater. Once up to temp I added the new saltwater slowly until the container was full (probably 1:3, same salinity, temp slightly higher than what she was in as the container was sitting out for a few minutes) and she moved from gasping at the top of the water to down lower in the container.
Monitored and kept slowly switching out water. I ran all my tests while she was in there and added a powerhead to help get O2 into the water.
She died within the hour. She kept breathing heavily and quickly and she began to curl which was the fatal sign to me.
Here are all the parameters at the time of discovery:
Salinity: 1.025
Temp 78.6F
pH: 8 (API)
Ammonia: 0 (Salifert)
Nitrite: 0 (API)
Nitrate: 0-5 (API)
Phosphate: 0.05 (Hanna)
Alkalinity: 145ppm (Hanna)
I noticed the Gramma was often hiding I didn’t really see her much at all unless feeding. I fed frozen mysis shrimp and flakes. I had added 2 clowns a couple days ago. This Gramma was only in the tank for about 2 weeks.
*edit: I wanted to add I’m having a bit of a bacteria bloom so I suspected low O2, but I do have flow from the 2 pumps and a 6W powerhead on the lowest setting across the top of the tank*
Notes I got a cleaner shrimp at the same time as this Gramma and he is doing great, all corals are open and happy, clowns are swimming around, snails are dispersed throughout the tank (not hanging out around the top) 2 crabs that are also still kicking.
I’m trying to figure out what happened and I know it’s likely super hard to do so. With fish just being added I want to try and prevent this moving forward. It all happened so fast too.
Here are photos postmortem.. apologies if that’s not allowed or jarring.
I see maybe some knicks on the fins? Maybe from another tank mate?

I have a 20-gallon IM Nuvo. It’s cycled and been running for almost 4 months. I slowly have been adding corals and snails.
I decided to get my first fish (2 weeks ago) (after much consideration) and started with a Royal Gramma. It was smaller and an LFS. The gramma seemed to be doing ok, it would come out during feeding and sometimes as the lights dimmed. Yesterday I did see her hanging out in her usual cave but it is toward the back of the tank so I can’t really see her too well.
This morning I went to feed and I he Gramma was no where to be found. I killed the filters to look from the top down and found her (in her usual corner) but not moving much. I waved some water in her direction and she shot up to the surface and got sucked to the filter grate.
I immediately put her in a separate container with water from the tank and spun up the heater on some fresh saltwater. Once up to temp I added the new saltwater slowly until the container was full (probably 1:3, same salinity, temp slightly higher than what she was in as the container was sitting out for a few minutes) and she moved from gasping at the top of the water to down lower in the container.
Monitored and kept slowly switching out water. I ran all my tests while she was in there and added a powerhead to help get O2 into the water.
She died within the hour. She kept breathing heavily and quickly and she began to curl which was the fatal sign to me.
Here are all the parameters at the time of discovery:
Salinity: 1.025
Temp 78.6F
pH: 8 (API)
Ammonia: 0 (Salifert)
Nitrite: 0 (API)
Nitrate: 0-5 (API)
Phosphate: 0.05 (Hanna)
Alkalinity: 145ppm (Hanna)
I noticed the Gramma was often hiding I didn’t really see her much at all unless feeding. I fed frozen mysis shrimp and flakes. I had added 2 clowns a couple days ago. This Gramma was only in the tank for about 2 weeks.
*edit: I wanted to add I’m having a bit of a bacteria bloom so I suspected low O2, but I do have flow from the 2 pumps and a 6W powerhead on the lowest setting across the top of the tank*
Notes I got a cleaner shrimp at the same time as this Gramma and he is doing great, all corals are open and happy, clowns are swimming around, snails are dispersed throughout the tank (not hanging out around the top) 2 crabs that are also still kicking.
I’m trying to figure out what happened and I know it’s likely super hard to do so. With fish just being added I want to try and prevent this moving forward. It all happened so fast too.
Here are photos postmortem.. apologies if that’s not allowed or jarring.
I see maybe some knicks on the fins? Maybe from another tank mate?

