Losing cat fish unknown reason

[hooliganATV]

Hi all,

I recently move my tanks around, the new cat tank is the same volume but different size tank. It was a one for one on substrate, filters, decore but in the last week I have lost one 5" Batrochoglanis raninus and two SA bumble bee cats. Only indication is like a white/ cloudy area around the mouth. The tank has other fish and they all seem fine all water levels are good and I did a 50% WC when the first fish died. I'm stumpt any help much appreciated.

Sorry for not link fish to cat-elog I will do this on my laptop late I couldn't work it out on phone

[Mol_PMB]

Can you provide a bit more information, such as that listed in the sticky:
http://www.planetcatfish.com/forum/view ... f=5&t=4305

Otherwise we're just guessing, and my guess would be that they have had to re-establish territories in the new tank, and have been fighting. But it could be so many other things.

[hooliganATV]

Hi mate

Nitrite were 5ppm
Nirates were 20ppm
Ammonia unknown

Set up is 60G, 4ft x20"x15" semie planted loads of drift wood. It was set up 10days ago. All the substrate was from the previous tank which was 55G but larger surface area and not as deep.
Only thing added was a larger bit of drift wood but this was clean and left in my 180g for a couple of weeks to sink it with no effect on them fish. Filtration is the same I moved it from the last tank its a 1200 lph internal and again no problems with that before. Tanks were swap in a matter of 3hrs. Other tanks mates are 4 yoyo loaches, 1 Bristlenose plec 3 angels and 4 tiger barbs and there is one Batrochoglanis raninus left

Only two things I can think off is a filter crash but in 3hrs I have never had this before, could be that the substrate wasn't cleaned as well as I though and storing it up has crashed the tank or its a territory dispute and the last raninus is picking them off or stressing them to death but not witnessed any thing. All other fish are happy with no noticeable faults

[Viktor Jarikov]

I must be missing something. All fish should be dead within hours or days at 5 ppm nitrite. How was that measured? I always recommend a liquid test tube test.

Not knowing ammonia level will essentially prevent making a first step in the analysis of what's going on.

[dw1305]

Hi all,

Only two things I can think off is a filter crash but in 3hrs I have never had this before, could be that the substrate wasn't cleaned as well as I though and storing it up has crashed the tank or its a territory

Sorry to hear of your losses.

It is most likely to be an oxygen issue due to the biological filtration not being full re-established. Cleaning the substrate has probably removed some of the biological filtration capacity.

I'm not a great fan of internal filters, even a big chunky one doesn't have a great volume of filter media available.

Can you raise the filter so the water is splashing into the tank? (or add a venturi device to the filter) and add an air-stone?

The oxidation of ammonia to nitrate (NH4+ > NO2- > NO3-) is an oxygen intensive process, and if you have a situation where the biological filtration is compromised the rate of oxygen diffusing in at the water surface can't replenish the dissolved oxygen and oxygen levels fall a long a gradient from the waters surface to the bottom of the tank. Large, bottom dwelling, nocturnal rheophilic fish are particularly at risk from this, mainly because they are reluctant to swim to the more highly oxygenated surface layers of the water.

There is a more complete discussion of this in "A catfish keepers guide to dissolved oxygen"(http://www.planetcatfish.com/shanesworl ... ved+oxygen) and have a look at "Aeration and dissolved oxygen in the aquarium" (http://plecoplanet.com/?page_id=829) and Stephan Tanner's article on "Aquarium biofiltration" (http://www.swisstropicals.com/library/a ... iltration/).

cheers Darrel

[TwoTankAmin]

A couple of things. Nitrite poisoning looks like a fish is suffocating, but this is not from lack of oxygen in the water. The most important sign of nitrite poisoning is that fish will be gasping for air at the surface. Here is how it works:

Brown blood disease occurs in fish when water contains high nitrite concentrations. Nitrite enters the bloodstream through the gills and turns the blood to a
chocolate-brown color. Hemoglobin, which transports oxygen in the blood, combines with nitrite to form methemoglobin, which is incapable of oxygen transport.
Brown blood cannot carry sufficient amounts of oxygen, and affected fish can suffocate despite adequate oxygen concentration in the water. This accounts for the
gasping behavior often observed in fish with brown blood disease, even when oxygen levels are relatively high.

from https://srac.tamu.edu/serveFactSheet/110

So my first question is did you notice fish at the surface a lot or hanging out in the return flow from the filter? However, I would be surprised if nitrite affected only one species in a tank. Next, regarding the test result of 5 ppm. If you are using the API nitrite kit, it stops at 5 ppm, so you don't know if your actual level was 5 or maybe a lot more.

The white around the mouth is typical of columnaris aka "mouth fungus" some forms can kill fast. Have a read here: http://animal-world.com/encyclo/fresh/i ... outhFungus
Again, This should likely affect other species, not just one. Akso, you saw the fish and see those remaining, so you need to decide if this might be what you are seeing.

Finally, the one thing you do not have numbers on is ammonia. If all your work wiped out half of the nitrifying bacteria, you can expect an ammonia spike which is why you have nitrite. However, between the time it happens and the ammonia bacteria/archaea reproduce to deal with it can be a day or less. So ammonia may have been the culprit. However, your plants sould contribute some amount of ammonia consumption capacity to your tank.

When it comes to any of the 3 nitrogen compounds in tanks, there is no universal level at which any given species will suffer or succumb. Different fish can tolerate different levels for different amounts of time.

If the problem were low DO I would also have expected other fish to show some symptoms as well even if they did not die. Those symptoms would be similar to nitrite poisoning. So I would ask the same question, did you notice the behavior described above?

This is about all I can think of at this point. Between Darrel's thoughts and what I have added, I think one of these things might be to blame. I share his disloke for internal filters.

You can deal with nitrite by adding chloride to the water. It will block the nitrite from getting into the blood. Adding a very small amount of salt will do the trick. I can give you instructions for doing diluted testing for nitrite if your kits still reads at its maximum level and you do not know how to do this.. You need to know the actually ppm of nitrite to know how much salt is required. I ran a quick estimate using 50 gals- your tanks never hold the amount of water they are labeled as. I assumed 10 ppm of nitrite and aimed to have 10 times the chloride in the water as nitrite. The amount of salt you would add would be 1 level tablespoon + 1 level teaspoon (about 29.1 grams). I use plain old table salt.