New purple firefish issue

cst0215 · 2026-09-28T23:35:42-0400

I hope somebody can give me some advice. I just bought a purple firefish and introduced into my qt tank 2days ago. The tank was emptied and filled with new saltwater of 1.025 ppm salinity. It was swimming fine at my lfs, but in my tank he is just laying in one spot on the bare glass. Bottom next to a pvc hide. It does not seem to be breathing heavily. Is this normal behavior? Temp is around 76 degrees Fahrenheit. Thank You

Tahoe61 · 2026-09-28T23:48:14-0400

Try giving it more cover/hiding spots, diminish lighting if applicable.
They are one the more shy fish, and more difficult to acclimate in my experience.

#fishmedic

Reef Jedi · 2026-09-28T23:50:05-0400

I agree with the above. They can be very shy and I bet it’s trying to hide.

Mr. Mojo Rising · 2026-09-29T07:20:59-0400

"The tank was emptied and filled with new saltwater"

Is the tank cycled?

cst0215 · 2026-09-29T08:04:52-0400

Thanks all for the replies. The tank is a 10 gallon used for quarantine. I start out with no medication. Once the fish are acclimatized I then ramp up chelated copper to a max of 2.25 ppm approximately. The tank is no sand, but has several bags of ceramic rings that have a population of denitrifying bacteria and this usually allows it to have no ammonia. If it does I do frequent 20% water changes. There are several pvc fittings inside, and plastic plants to allow the fish to hide. I do have a light, but it’s usually only on in the evening when I feed so I can observe

The firefish appears healthy so far, just lays on bottom and will not eat. When I brought it home I put it in an external acclimation box and replaced a small amount 1/4 cup of water that was in the bag with the tank water around every 10 minutes until I felt that the box had mostly tank water. It was swimming fine at the store.

Bear22 · 2026-09-29T08:13:24-0400

I would ditch those ceramic rings. Especially, if they are white as they could be leaching trace aluminum. If they are a quality ceramic rings (Eheim as an example) then I wouldn't worry about it.

These are sensitive fish (I have an Exquisita), but are quite happy and active IF they have agreeable tank mates and a nice cave where they feel comfy and safe.

Jay Hemdal · 2026-09-29T08:17:22-0400

cst0215 said:
Thanks all for the replies. The tank is a 10 gallon used for quarantine. I start out with no medication. Once the fish are acclimatized I then ramp up chelated copper to a max of 2.25 ppm approximately. The tank is no sand, but has several bags of ceramic rings that have a population of denitrifying bacteria and this usually allows it to have no ammonia. If it does I do frequent 20% water changes. There are several pvc fittings inside, and plastic plants to allow the fish to hide. I do have a light, but it’s usually only on in the evening when I feed so I can observe

The firefish appears healthy so far, just lays on bottom and will not eat. When I brought it home I put it in an external acclimation box and replaced a small amount 1/4 cup of water that was in the bag with the tank water around every 10 minutes until I felt that the box had mostly tank water. It was swimming fine at the store.

What was the salinity/specific gravity that the firefish was in at the store?

cst0215 · 2026-09-29T11:17:53-0400

Jay Hemdal said:
What was the salinity/specific gravity that the firefish was in at the store?

I’m not sure. I am new to this and didn’t think to check…seems obvious in hindsight sight! Will do so from now on. I might be able to ask the store,but to be honest I don’t know how much I trust there abilities with saltwater fish. I am very limited in shops where I live.

If it was a problem with drastically different salinity, do you think the fish would still be alive after approximately 60 hours?

Jay Hemdal · 2026-09-29T14:54:12-0400

cst0215 said:
I’m not sure. I am new to this and didn’t think to check…seems obvious in hindsight sight! Will do so from now on. I might be able to ask the store,but to be honest I don’t know how much I trust there abilities with saltwater fish. I am very limited in shops where I live.

If it was a problem with drastically different salinity, do you think the fish would still be alive after approximately 60 hours?

Marine fish don’t handle rises in salinity well. Many dealers hold their fish in lower salinity to save money on salt and to partially suppress disease. That’s a mistake, because people buy those and put them into full salinity. Even with acclimation, it causes temporary stress and an even kill some smaller fish. Generally, the fish recover in 3 days.

Now, I can’t say for sure that is the issue here, I was just trying to rule it out.

cst0215 · 2026-09-29T15:47:24-0400

Jay Hemdal said:
Marine fish don’t handle rises in salinity well. Many dealers hold their fish in lower salinity to save money on salt and to partially suppress disease. That’s a mistake, because people buy those and put them into full salinity. Even with acclimation, it causes temporary stress and an even kill some smaller fish. Generally, the fish recover in 3 days.

Now, I can’t say for sure that is the issue here, I was just trying to rule it out.

Do you think there is anything I should be doing? I hate to see it just lay there and starve to death