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What killed my fish??

13K views 35 replies 8 participants last post by  amazon21 
#1 ·
This is from my previous post.

Hey, I'm new to this forum, and I was hoping I could get some advice on redoing my aquarium.

I currently have a 29 Gallon aquarium glass tank. I started out with a couple of fake plants, and used a
Zebra Danio to cycle the aquarium, and later on added 3 more of them. There were absolutely no problems. I gradually added neon tetra's to the tank as well, 1 a week until i got to 4. The neon tetra's were fine as well. 1 month later the trouble started. One of my Zebra Danio's got some kind of disease. His stomach area kind of caved in slowly, and he had fin rot. Next it happened to my other Zebra danio's and eventually , in 3 weeks, all my danio's were dead, and I was left with 4 Neon Tetra's. These Neon Tetra's were next. Soon, after a month, the exact same thing happened to my Neon Tetra's. I kept changing the water every 2 weeks, but the fish would still die. I did about 2, 50% water changes because I read that water changes should be able to get rid of many diseases. Unfortunately that didn't solve the problem. Over the next month those fish died, and now I'm left with an empty tank.
:BIGweepy:


I don't know exactly what mistake I made, but there is some bacteria in my water that is killing off even the most hardiest of fish. So my first step for getting my amazon biotope aquarium is to rid my tank of this disease. I still remember how the last fish looked when it died, it's stomach area kind of caved in, it was VERY skinny, even if I fed it (I did not overfeed, or underfeed), it's fins had fin rot, and its eyes kind of bulged out. Im not exactly sure what disease it is, but it looks similar to
Neon Tetra disease or Fish TB. Either way, I don't think medications will do the job, so Im going to try and start over.

Does anybody have any idea what killed my fish?? I think they got that disease because the water quality was bad since I did not change my filter cartridge
 
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#2 · (Edited)
Well, I can say the last thing you said was wrong.... don't change the filter cartridge... well, it depends. Let me explain.... The filter cartridge houses the, I believe it's called "nitrifying bacteria," that is bacteria that breaks down fish waste (ammonia) into nitrite, and then the nitrite further into nitrate. Each subsequently less toxic. So, you want that bacteria. If you take out the cartridge then you take out a large amount of that bacteria and cause an ammonia spike. You can take it out however if the filter has another type of sponge, biowheel, or 2 cartridges then you can take out one every once in a while and change it. I wouldn't really risk it. I'd just take the filter cartridge out and wash it every 3rd time (that's what i do) or 2nd or every time you change your water. Rinse it in the bucket or wherever you drain the water. If you run tap water with chlorine over it you risk killing the bacteria. So just swish it around in the water to clean it off. It's not necessary and sometimes bad to change the filter cartridge....

Anyways, it might have been from bad water quality. Probably not from not cleaning the cartridge or changing it though.did you change the water at all in that 1 month+ period? 4 danios and 4 neon tetras seem like they'd hardly create much of a bioload so idk. Maybe from buying so many from the pet store at different times you brought in some kind of disease?

Btw, I'm not very good with diseases so I can't name the disease you described, sorry.

Edit: also, you are right. Clean water does help cure and prevent disease. Clean water helps boost the fish's immune system. It's not always a cure-all though when the fish already have a disease. It's a very helpful preventative though.
 
#3 ·
I normally clean the tank every 2 weeks, but this time, I waited about 4 weeks because I was pretty busy, and I clean my 30 gallon tank using the bucket method which takes FOREVER( about 1.5-2 hrs). I've heard about the wash your filter cartridge thing before. I have an aqueon power filter 30, and while its not nearly as good as the bio-wheel, it does have a bio-holster, which is this thing in front of the filter that is used to make a better bacteria bed than what you would find on a filter cartridge.
 
#5 ·
Hmmm might be safe then to sitch cartridges but in my opinion is a waste of money... from what I've read and heard and experienced it is unnecessary.

Anyways, still, the bioload would be pretty low for those 8 small fish so 4 weeks should have been fine I'd think.

Also, on the water changing method - I have some suggestions that might be helpful. Buy some long tubing at a lowes or home depot. Get it so that it is long enough to reach the bathroom or a window or door and drain outside. This takes one step out when draining it into a bucket. You can also buy tubing that reaches from a sink or something and fill your fish tank up directly (I'd only do this is you buy a digital thermometer to be able to quickly get the temperature the same as inside the fish tank), then attach it, and keep an eye on the temperature and fill the tank up. :) Then add the stress coat. Could help make water changes easier for you. I so far only drain the water out that way but i know lots of people fill it up. I never thought of this till I came here so you can look into that if you wish. ;)


oh yeah, i think it could be the pet store thing, because I don't have a hospital tank to quarantine but.....

- the neon's were the last ones to go in there, and were in the tank for about 3-4 weeks before the first fish died

-the first fish that died was one of the danio's, the 4th one that i bought. I bought it almost 1-2 months before it died, the neon's were the last to die.... If it was from the fish store, the/ a neon would have been first.
it could have been carried in the water but other than that I don't know. I'm sure others will be here to offer answers soon. ^_^
 
#4 ·
oh yeah, i think it could be the pet store thing, because I don't have a hospital tank to quarantine but.....

- the neon's were the last ones to go in there, and were in the tank for about 3-4 weeks before the first fish died

-the first fish that died was one of the danio's, the 4th one that i bought. I bought it almost 1-2 months before it died, the neon's were the last to die.... If it was from the fish store, the/ a neon would have been first.
 
#9 ·
I do not know about what kind of disease killed your fish. I hope someone with more knowledge can help, but, and this is in the sticky note for information to give, they need to have some water parameters to know exactly where your water is at. PH, Ammonia, Nitrite/Nitrate.

Personally, I think every two weeks is too long a stretch. Since i do not use carbon, I try and do a water change on the two tanks with no carbon every other day.

It is possible that the fresh water comes as a shock and stresses the fish. They have adapted slowly over the two weeks to the deteriorating water conditions and all of a sudden there is a big infusion of fresh water.

More frequent water changes.

If I run into information elsewhere, I will try and post it back here.
 
#12 · (Edited by Moderator)
No, I would not recommend chlorinated tap water. It might kill the bacteria, but would more likely harm your fish. I would just continue water changes/and if anyone else can add better info, please do.. I'm just scrambling around here. Stress in and of itself is not an illness (although I think it could be debated) but it weakens the fish (any organism that is stressed, frankly) and you will get an opportunistic disease take hold that, if the fish were NOT stressed, their immune system could fight it off.
 
#13 ·
there are no fish in the tank. I just got all the water out of the tank. I'm probably going to put water in the tank but I have one question. I think the disease is bacterial, so I want to put hot water in the tank, but is that a good idea?? Im thinking about water from 90-100ish degrees.
 
#14 ·
I think most bacteria could survive water in that heat range.
If there are no fish and the tank is empty you could use a bleach solution, empty the tank and let it air out completely. The bleach (chlorine) will evaporate.
 
#16 ·
A mild (10%) bleach solution is safe for disinfecting aquariums. Fill the aquarium with the bleach solution, let it soak for about 10-15 minutes, drain, fill with clear water and let it soak a bit, drain, rinse with clear water then let air dry completely. Also, use a double dose of water conditioner when you refill it for final use.
 
#18 ·
Just get plain ole bleach (no dyes or fragrance, etc). Plain tap water won't disinfect like bleach will.
 
#20 ·
bleach... of course. if your a skeptic think about the hospital they use a lot of bleach.1 part bleach to 9 parts water.
 
#23 ·
bleach it dude
just remember that however long you soak with the bleach solution you have to soak equally long with clean water to remove all bleach bits

and heat doesn't kill bacteria...well it does...but not heat in the ranges that will come out of a faucet...anything hot enough to kill the bacteria would probably also damage the tank imo
 
#28 · (Edited)
A few days might be overkill...soak for about four to six hours...that's how long it takes to kill staphlococci, streptococci, all other run of the mill cocci, bacilli, spirilla, etc. granted those are human bacterial infections but if four to six hours will take out mycobacterium fortuitum furunculosis then it should be enough to handle fish bacteria...just soak with fresh water as long as you soaked with bleach water afterwards to get all bleach out...so bleach four to six hours, fresh water four to six hours...
 
#34 ·
If you soak the gravel make sure you let it air dry completely (in the sun if possible). You can spread it out onto a plastic trash bag and set it in the sun. You should not be able to smell any chlorine. Also, When you're ready to set up your tank use a double dose of dechlorinator just to be safe.
 
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