fish dying...need help

I have had 3 fish die in almost exactly the same fashion and I need help getting to what I am doing wrong. All params within norms, all 3 days to one week old fish. all eating. all fish enter and behave seemingly healthy for at least a few days and then suddenly they become withdrawn and they die shortly after (refusing to eat while they are withdrawn). Could this come about from under/overfeeding (nitrates less than 10ppm)? could stress from acclimation kill them on such a belated basis? what is driving this?

additional info:
hermits, snails, mandarin, flaming prawn all doing well for months with no known hitchhikers (got rid of them). no physical sign of damage to the fish, and no obvious bacterial symptoms. i feed once a day generally. could the new guys be starving to death?

 

By any chance have you seen any aiptasia in your tank?

I might as well ask it, since i've had the same problem in the past.

I really don't think your fish are starving bro. I feed mine once a day at 6:00 pm. Never had a fish in my time die from starvation. Go around and check for those critters. Could be something else easily though. Might as well be safe.:

 

Do you check you water parameters yourself? You should bring it to the fish store and have them test it for you. I've heard that some people's testkit over time fail for them because of its age.
Also when you take out the fish, are they any signs of sickness or any kind of damage on their skin?

 

I have seen a small one (less than one inch) but I left it alone to reduce the chance it would spread. what surprises me if they are the cause is why only recent additions die in that time frame (could be coincidence).

 

no signs of damage at all. I have tested myself and had them tested independently. i am really at a loss

 

it could be you placing sesitive fish in an immature tank??

 

ok, anything specific tho?

 

Spartan, how long has the tank been up?
Even if nitrates are < 10 pmm, how about the ammonia, nitrite, Alkalinity and pH?
Any other info such as pounds of live rock, tank size, water flow and filtration may also be helpful in helping you figure out this problem.

 

35 lbs of live rock, ammonia nitrite 0, PH 8.3. its a 25g nano, have another tank that has very similar specs with no problems (55g). what is a typical survival rate of fish?

 

Well, it depends on a lot of factors sometimes.
Where the fish come from and how they are collected off the reefs.
Some collectors have used toxins to get the fish to come out, and the fish slowly die of it. Others may have internal diseases, parasites, etc that you don't see and the fish store doesn't treat for. Your best chances of having any fish survive is to buy tank-bred and raised fish. They seem to more resilient to diseases. What type of fish have been dying?

Do you have surface agitiation, good flow, maybe an airstone, etc.. enough to keep a high enough oxygen level up in the tank? Salinity level?
What is the temperature of the water? You should keep it around 78-80 degrees, with minimal fluctuations as possible.