fish dying mysteriously

jenricae

AC Members
Dec 27, 2005
163
0
16
Vancouver, BC Canada
Hi,
I have a 35 gallon freshwater tank. I had a few fishes in it - tiger barb, gourami, ottos. Since the summer all have died. one by one. What's wierd is that one died and then there will be a month before another started to die. I have one loach left in the tank. Before i restock my tank, i'd like to make sure that there isn't anything wrong. All the tests (amonia, etc) check out fine. Is there a way i can "clean" the tank before adding fish. I'm thinking that i should do a bunch of water changes and give the filter a thorough cleaning. Any help is appreciated.
Thanks in advance.
 
How often do you do water changes? How do you do the water changes? Anything noticable on the corpses? What are the actual numbers for the test results? Temperature? Filtration type and maintenance?
 
If every fish has died bar the one cafish, then id be expecting him to go soon, unless you start to treat or diagnose the problem.

check your levels, check for unexpected things in the tank, check for everything that shouldnt be there.

as for cleaning your tank, you can do a massive water change then leave the tank to cycle for a while and check the levels daily. I usually leave my tanks for 1-2 weeks to cycle prior to adding anything.

Or

the complete overhaul, which is a final resort, this is remove all water, all gravel and do a deep clean. as i say THIS IS A FINAL FINAL LAST CHANCE option.

Ive had to do this once due to getting some sorta worm in the gravel i couldnt find. bascially you boil the gravel, wood and any stones then rebuild the tank from bottom up.
 
Thanks for the input.
The last fish that died had one red sore and one rotten eye. It is really weird, the loach is very healthy. I suspect that i need to do a big water change and maintain the tank better. I've been slacking off a bit the last while, and i think i've paid a price for it.
 
The rotton eye could be a parasite...if the eye burst in the tank then the parasite will be in the water/gravel.
 
You don't have any assurance that this is a parasite, so there's no way, short of starting the tank over, to make sure it's dead. On the plus--many parasites are multi stage, meaning they require more than one host to complete their life cycle, and most are host specific, so the life cycle is probably short circuited in a closed system.

However--without knowing if you actually have a parasite or not, there really isn't any medication that can be recommended. If you didn't have that single loach left, I suggest just tearing the system down and starting over--probably still going to be your best bet, if you can find an alternate home for the loach.
 
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