Adding fish after fish death

brillypowr · Sep 11, 2018

I have a 10g nano reef tank (9months old) and I typically keep 1-2 fish and mostly corals. 2 days ago, my Davinci Clown fish started acting odd (breathing heavily, rubbing sand). Now thinking back, I did notice a white stringy looking poop but didn't think much of it. He had only been in the tank a month or so. I checked my levels and salinity which were all perfect. The fish died overnight before I could get medicine

Also random, one of my emerald crabs was dead too. The snails, hermits, other emerald crab, corals were/are fine.

After googling why my beloved fish died, I came up with possible internal parasite. My question is, how long until I can add another fish to the tank? There are no fish in the tank now. Will any possible parasites linger and infect a new fish? Should I dose the tank with something? I did a partial water change and my levels are fine. I read that some parasites can live dormant in the tank for months. What should I do?

Porpoise Hork · Sep 11, 2018

White stringy poop is typically a sign of a bacterial infection. However with heavy breathing and rubbing the fish could also have had marine velvet. To be safe you want to leave the tank in its current state for at least 4-6 weeks. The issue is with the corals and inverts in there you cannot treat the tank with copper. So unless you want to tear it down, sanitize and start over, wait. Give what ever parasite that may have made it into the water column from the clown the chance to go through its life cycle and starve out.

Sucks but the last thing you want to have happen is introduce a new fish to the tank and have the same thing happen.

USMC 4 LIFE · Sep 11, 2018

brillypowr said:
I have a 10g nano reef tank (9months old) and I typically keep 1-2 fish and mostly corals. 2 days ago, my Davinci Clown fish started acting odd (breathing heavily, rubbing sand). Now thinking back, I did notice a white stringy looking poop but didn't think much of it. He had only been in the tank a month or so. I checked my levels and salinity which were all perfect. The fish died overnight before I could get medicine Also random, one of my emerald crabs was dead too. The snails, hermits, other emerald crab, corals were/are fine.

After googling why my beloved fish died, I came up with possible internal parasite. My question is, how long until I can add another fish to the tank? There are no fish in the tank now. Will any possible parasites linger and infect a new fish? Should I dose the tank with something? I did a partial water change and my levels are fine. I read that some parasites can live dormant in the tank for months. What should I do?

White stringy poop is indicative of internal parasites.

Can you elaborate further on “my levels are fine”. People often say this and fail to check all their levels (salinity, PH, temp, CA, ALK, Mag, Nitrates, etc)

Are you quarantining all fish, corals and inverts before adding them to your tank? If not, then you’re risking having sick fish.

vetteguy53081 · Sep 12, 2018

Appears to be velvet. Recommended is 30-45 days and you could treat with reef safe product called PRAZI-PRO.

Porpoise Hork · Sep 12, 2018

USMC 4 LIFE said:
White stringy poop is indicative of internal parasites.

Can you elaborate further on “my levels are fine”. People often say this and fail to check all their levels (salinity, PH, temp, CA, ALK, Mag, Nitrates, etc)

Are you quarantining all fish, corals and inverts before adding them to your tank? If not, then you’re risking having sick fish.

In the OP's case a QT tank may not be feasible since tank is a 10g nano. The best option he has is to leave it fallow for at least a month to month and a half. Then see about adding a new fish or two to avoid reinfection. The best option for new fish are to either find a local club member who is selling something that will be OK for that tank size, or work with the LFS to see if they can QT the fish for him for at least 10-14 days to make sure it's not infected. Many LFS will do this for a small fee provided they have a spare QT tank available.

Big G · Sep 12, 2018

Here's one you may want to bookmark. Humblefish's "Fallow Period" advisory:

Going Fallow

The reason to go fallow (fishless) is to eliminate a fish disease from your DT (display tank). Going fallow works because you are denying the disease a fish host to feed on, essentially starving it to death.

In order to go fallow you must remove ALL fish from your DT. If just one fish is left behind, even a “disease resistant” species, then going fallow is for naught because the disease will continue its life cycle. Corals/inverts can be left in the DT, as those are not capable of hosting - although some are capable of “housing” the encysted stage of certain parasites for a period of time (see “Fallow Periods” below). It is important to continue to feed your corals/inverts while going fallow, and also put a pinch of flake or pellet food into the DT every 2-3 days to feed nitrifying bacteria in the absence of fish poop. Continue to do everything normally with your tank while going fallow; although you may wish to go lights out if you are running a fish only system (just don’t forget to feed that bacteria!)

Fallow Periods - Below is the general consensus fallow periods for all diseases that require it. In most cases, it is the longest known time period that the encysted stage can survive on corals, inverts, rocks, substrate without a fish host to feed on. The fallow period starts when the last fish is removed from the tank.

Black ich (turbellarian worms) - 4 weeks
Brooklynella aka “Clownfish disease” or “Brook” - 6 weeks
Flukes (monogenean worms) - 4 weeks
Ich (Cryptocaryon irritans) - 76 days
Uronema marinum - No fallow period, as it does not require a fish host to survive. It is an opportunistic parasite that strikes when a fish’s immune system has been compromised. Uronema mainly affects damsels (especially chromis) and clownfish.
Velvet (Amyloodinium) - 6 weeks

During the fallow period, the fish must be quarantined and treated for whatever disease(s) are afflicting them (see links below). Successful treatment is imperative to avoid disease(s) from being reintroduced into the DT:

https://www.reef2reef.com/forums/fish-disease-treatment-diagnosis/189284-fish-diseases-101-a.html

https://www.reef2reef.com/forums/fi...is/189658-treatment-options-my-two-cents.html

Quarantining all future livestock purchases is also very important to avoid having to go fallow again in the future: https://www.reef2reef.com/forums/fish-disease-treatment-diagnosis/189815-how-quarantine.html

After the fallow period has ended, you can return your fish to the DT. I recommend doing it one fish at a time, spread out over a couple of weeks. This will give your bacterial levels time to adjust to the added fish bio-load, and avoid a potential mini-cycle/ammonia spike. I also prefer to add back smaller fish first, so they are established ahead of the larger, more aggressive ones.

Do be sure to closely monitor your ammonia levels while adding fish back. I advocate using a Seachem Ammonia Alert badge for constant monitoring: