Fungus Killing Fish My Fish?

[orangegecko]

So this has been growing on my mopani driftwood...
 

 

 
I heard that it is harmless but want to get other opinions... 
 
I recently put fish in my tank last weekend (sunday-12 neons and 6 otos) which has been cycled and my readings are what they should be via my own test kit (0 ammonia, 0 nitrite and about 10 nitrate, pH 7.6-8). 
 
6 of the neons died within 4 days (weds was the last fatality of neons- i have some pics of the live ones if needed- and my readings have been consistent with what I posted above -tested water every couple of days)...  Friday 1 oto died and yesterday (saturday) another died. 
 
Went to the LFS and had them test my water and they said everything was what it should be and I mentioned something about the fungus growing on the driftwood.  They said that might be what is causing the deaths and that I should get some Tetra fungus guard to clear the fungus and bacteria (if there is any)...  They also say to add 6 or fewer fish every week which might help with stress...  I'm not sure what to think about that...
 
Here are a couple pics of one of the otos...  It was still barely alive and 'breathing'.  The belly looks full and there is some red by its fin (my tank has little to no bacteria so I have been putting Topfin Algae thins in it for them to eat (although I have not noticed them eating any...)
 

 

 
Any info, questions or comments greatly appreciated!

 

[BerryAttack]

did you cycle the tank?
neons and otos need a very mature tank to survive in.. 
so because you have no fish do a fishless cycle if you already haven't. when doing a water change treat the water before adding it in and this must be done every time or the chlorine etc will kill the fish.
never rinse out your filter with tap water.. do it when doing a water change to keep the healthy and good bacteria. 
 
**and for the growth on the wood it is normal, everyone gets it when having new wood. just go in and scrape it with your nail and remove it from the tank. it shouldn't be harming your fish unless the wood was soaked and treated with chemicals.

 

[star4]

I am taking this is a newly cycled tank? suddenly adding 18 fish in one go could cause an ammonia spike resulting in the deaths, which after the deaths = less fish and the filter "caught up" with the ammonia producing 0 results on a test. The ammonia spike could of happened inbetween you testing the water and its that spike that has caused the damage to the fish not the wood I am afraid.
 
 
You should always only add fish a few at a time. Also as Berryattack states, neons and otto's need a mature tank, not newly cycled.

 

[orangegecko]

did you cycle the tank?
neons and otos need a very mature tank to survive in.. 
so because you have no fish do a fishless cycle if you already haven't. when doing a water change treat the water before adding it in and this must be done every time or the chlorine etc will kill the fish.
never rinse out your filter with tap water.. do it when doing a water change to keep the healthy and good bacteria. 
 
**and for the growth on the wood it is normal, everyone gets it when having new wood. just go in and scrape it with your nail and remove it from the tank. it shouldn't be harming your fish unless the wood was soaked and treated with chemicals.

 
The tank has been fish-less cycled for a month (I have added ammonia every few days to keep the bacs fed) and finally had the chance to add fish last weekend.  And there are fish in the tank already.  I treat the water every time I change and add more.  I rinse my filter media in tank water...  So maybe the tank isn't mature enough to support them as being the first fish then.
 

I am taking this is a newly cycled tank? suddenly adding 18 fish in one go could cause an ammonia spike resulting in the deaths, which after the deaths = less fish and the filter "caught up" with the ammonia producing 0 results on a test. The ammonia spike could of happened inbetween you testing the water and its that spike that has caused the damage to the fish not the wood I am afraid.
 
 
You should always only add fish a few at a time. Also as Berryattack states, neons and otto's need a mature tank, not newly cycled.

 
Yes the tank has been newly cycled and I see what you are saying with the levels and how it could have been missed...  The maturity of the tank is something new I haven't read or heard about...  What kind of fish would be able to handle a new tank better?

 

[coolie]

Keep re-checking the Ammonia for a spike. If you are worried about the fungus, take out the wood and clean it off with 2% Methylene Blue. Douse it and leave to stand for an hour, then rinse off as you don't want large amounts of Methylene Blue into the tank. That will cure one problem anyway and eliminate it from being the cause.

 

[star4]

Sorry I am confused, are there fish already in the tank? or were the neons and otto's the first fish? If you do have other fish what are they.
 
How often are you rinsing your filter media? you shouldnt need to do it every water change.

 

[coolie]

I actually think the shop selling you bacteria treatment for the whole tank was a really bad idea, esp. when there are already concerns about how cycled the tank it.

 

[orangegecko]

Sorry I am confused, are there fish already in the tank? or were the neons and otto's the first fish? If you do have other fish what are they.
 
How often are you rinsing your filter media? you shouldnt need to do it every water change.

 
The neons and ottos are the first fish in the tank.  My apologizes on saying that I have rinsed my media -i haven't (meant to write that i know to rinse in tank water when i do)...  one question i have is that it is an external canister filter, so when would be a good time-frame to rinse it and all the media in it?  3 months?  longer?

I actually think the shop selling you bacteria treatment for the whole tank was a really bad idea, esp. when there are already concerns about how cycled the tank it.

 
And they shouldn't have sold me all those fish too!  but then again the person selling them was young and might have been inexperienced like me! (nothing against younger people!)...

 

[star4]

With an external, if you are keeping small community fish you will not need to do it that often, some people wait until the flow slows down, some do it regularly every 3, 4 ,5 6 months depending on stocking.
 
You need a hardy type fish to start off with Danio's are usually pretty good for a new tank.

 

[orangegecko]

With an external, if you are keeping small community fish you will not need to do it that often, some people wait until the flow slows down, some do it regularly every 3, 4 ,5 6 months depending on stocking.
 
You need a hardy type fish to start off with Danio's are usually pretty good for a new tank.

 
Ok.  I think if I add any more fish I will add danio's.  Are they community fish as well?

 

[TwoTankAmin]

Both otos and tetras can be in horrid shape when you buy them. I do not hold with the idea that they need to go into a more mature tank if you have cycled a tank for weeks to establish the bacteria/cycle. Most people are not aware that most bacteria prefer living in a biofilm over being free swimming. The result is the bacteria in biofilms are protected against a lot of nasty things, especially when the exposure is short term.
 
The amount of chlorine in one's tap water is low and a short term wash in it of filter media will not wipe it out. leaving a sponge with bavcteria in it sitting in a bucket over night is a different proposition. As a rule of thumb, chlorine will harm fish before bacteria and chloramine will only put the bacteria to sleep but will kill fish etc. That said, it is always safest to rinse media in dechlorinated water as there can never be any question this way.
 
I have a friend who imports fish on a small scale. I get fish from her regularly and she explained it took her a while to find the best suppliers for tetras and similar small schooling fish. One trick I was taught by a gent in the fish game, both as a job and as a hobby, for over 50 years suggested when getting new tetras that I feed them live bbs for the first 10 days or so. This does help. But there is no replacement for getting healthy well fed stock to start.
 
Lastly, one of the benefits of doing a proper fishless cycle is the ability to stock fully when done. The idea that fish which come from waters where there is a rainy and dry season and therefore are regularly subjected to rapid parameter changes should not be hardy enough to go into a new but established tank is odd. The bigger danger is if they are imported from acid waters and have suppressed immune systems. The average fish keeper is not equipped to deal with this and also would have no clue if this was the case.

 

[Alm0stAwesome]

Well TTA you took the words right out of my mouth!
 
But just to reiterate what he said:
Adding dechlorinated water to your tank first then dechlorinating after - will not harm your fish (as long as you aren't running the dechlorinated water through your filter)
Fishless cycling prepares your tank to be fully stocked in one go. In fact, with the way we fishless cycle, we actually grow way more bacteria than a fully stocked tank would need so it's likely that bacteria actually dies back after being stocked as there isn't enough waste to feed it all. 
 
I agree with TTA on the point that you likely got weak/malnourished fish. Otos are notorious for being difficult to feed and if they were already in bad shape your sparkling new tank may have been too clean for them. 
 
That fungus is definitely not doing any harm...
 
What are the dimensions and volume of the tank?

 

[orangegecko]

Well TTA you took the words right out of my mouth!
 
But just to reiterate what he said:
Adding dechlorinated water to your tank first then dechlorinating after - will not harm your fish (as long as you aren't running the dechlorinated water through your filter)
Fishless cycling prepares your tank to be fully stocked in one go. In fact, with the way we fishless cycle, we actually grow way more bacteria than a fully stocked tank would need so it's likely that bacteria actually dies back after being stocked as there isn't enough waste to feed it all. 
 
I agree with TTA on the point that you likely got weak/malnourished fish. Otos are notorious for being difficult to feed and if they were already in bad shape your sparkling new tank may have been too clean for them. 
 
That fungus is definitely not doing any harm...
 
What are the dimensions and volume of the tank?

 
46 gallon bow front.  Tank dimensions, 36"W x 16"D x 20"H.

 

[Alm0stAwesome]

Danios would be fine in there as far as space goes as most varieties need a long tank for swimming space. I don't know a lot about danios but some of them are better in temperate rather than tropical tanks so be sure to do your research on which ones you get.