The Planted Tank Forum banner

Help, why are my fish dieing off?

1238 Views 15 Replies 8 Participants Last post by  williamsonaaron
75g tank that has been running for 3 weeks. I seeded the tank with filter media from a friends established healthy tank. I have serveral java ferns, wisteria, wendtii, chain swords, hairgrass, anubias, etc, a decent amount of plants I guess. For the last 2 weeks water has been steady at 7.4 pH, 0 ammonia, 0 nitrite, and between 10-30 nitrate.

EDIT: No CO2 or ferts are being used.

last Wednessday I added 8 harliquin Rasboras. That evening, I noticed one was swimming around eraticly with its mouth always open. It died about 3 hours after I introduced them. By the end of the evening I had lost 3, and by the next day all but 2 of them. All showed the same symptoms, they would swim eraticly with their mouths stuck open, and had a whitish growth around their mouths.

I went back to the store where I bought them, and the manager said it sounded like lockjaw. He also said he thought the name was saprolegnia. He said there was no treatment, and if the remaining fish were ok after 3 days, it would be safe to add more.

So, I got home and got on the internet and found out saprolignia was a fungus. We started treating the tank with pimafix and melafix just to be safe after reading up on them on several web sites.

When Sunday rolled around, I went back to the lfs where I got the fisrt set of fish, but they had no harlequins. I ended up purchasing 8 harlequins at a different location.

So, Sunday I 10 harlequin rasboras. For two days they swam about, seemingly happy as can be while we continued the recommended doseing of melafix and pilafix.

Today I get home from work and there are 7 dead. the three that are remaining, 1 seems rather lethargic and just hovering about. The other two (which are the remaining ones from the first purchase.) are swimming about the tank seemingly normal, but all of them are opening and closing their mouths a lot.

I have two hang on the back filters and decent water disturbance, so I can't belive it is an oxygen thing.

Just tested the water, and just like it was last night, 7.4 pH, 0 ammonia, 0 nitriite, and about 10 nitrate.

What is going on? There must be something wrong with my tank to have 2 large die offs from two different sources of fish. I can't see anything wrong with my water parameters that I can test for.

Any help is more than welcome, I hate not knowing what I have done wrong to these poor fish and want to get it corrected asap.

EDIT: I introduced my fish to the tank by over the course of 2 hrs slowley adding a small amount of the tank water into their bag, and then netting them into the tank after the two hours was up. Their bag floated in the tank durring this time.

Edit 2: I just used some test strips I had lying about to double check. My tank is reading

pH about 7.4
hardness: somewhere between 300-1000
Alkilinity: around 180

I checked this against my tap water which I used to fill the tank, and it reads

pH about 6
hardness: between 150-300
alkilinity about 80.

I am thinking I may have a rock leaching minerals into the water. I am pulling it out and doing a water change while I wait to hear if anyone has any ideas.
See less See more
1 - 16 of 16 Posts
IMO the most likely options are water parameter issues relating to your fluctuating hardness, and/or the harlequins you bought were already sick and the stress of transferring them to a new tank was too much for them.

At any rate, I'd wait at least a few weeks before getting any new fish, and I'd quarantine them before adding them to your tank.
you seeded the tank with media from a friend.. did you add a source of ammonia with it?

How long from when you seeded filter media to when you added the ammonia source or the fish. The nitrobacters that process ammonia to nitrate will die off in a few days with out a source of ammonia.

honestly the die off sounds like it happens too quickly for it to be ammonia build up from new tank syndrome but thats really all I can think of.
Are you quarantining these fish before adding them?
I bought a shrimp from the seafood counter and put it in to feed the bacteria I imported.

The highest detectable ammonia I ever saw was about 0.25 ppm. But that was at the very beginning. Only change the last 2 weeks or so has been fluctuating nitrate levels.

I find it hard to believe that 2 sets of fish from different suppliers all had such drastic die offs. These fish were from the 2 biggest fish specialty stores in the area. If they both have 80-100% sick fish in their tanks, they would not be able to stay in business. That's why I fear it is something wrong with my tank.

I did about a 30% water change and lost one additional fish since my first post. Now I only have the two survivors from the original group. They are swimming all around, and definitely not lethargic.
No, I didn't quarantine them. Before I added them the tank was empty.

I have a quarantine tank being prepaired with ammonia addition. I didn't want to use any media out of this tank in case there is something wrong with it.
To me, the fast progression of this disease suggests it's columnaris (bacterial) rather than saprolegnia (fungal); the visible symptoms are sometimes similar enough that they can be mistaken for each other.

Erythromycin antibiotic (sold at LFS as Maracyn II) is my treatment of choice. In my opinion, you should never rely on Melafix or Pimafix to cure any established disease.

It will be expensive to treat a 75g with Maracyn II, and probably too late to get bulk Erythromycin shipped to you. So now's a good time to set up that smaller quarantine tank, which you will definitely need in the future; because losing all or most of the fish in a fully stocked 75g due to a few new additions is heartbreaking. Seed it if possible. Perform daily water changes of 33% or so if there's any question whatsoever that toxins are building up.

And I too share the concerns about the long gap between seeding and fish introduction.

EDIT: I just saw the post about the quarantine tank. If you're going to use it for treatment, you'll need to discontinue and remove that ammonia.
See less See more
EDIT: I used Jungle Labs Right Start on my tap water.

I didn't add any packaged cycle starter. I imported established media, into a planted tank fed with a shrimp from the shrimp counter. When I saw changes in nitrates with no ammonia or nitrite, that signaled I had functioning bacteria from what I read, and that meant I was good to go for fish.

I can move the two remaining fish into a quarantine tank, but the two that are left are from the very first set of fish. I would have thought they would have died with the rest if they were going to die. I won't be able to get any medication now until after work in the morning anyway, so I guess I will have to see if they make it. Should I use anything from the main tank in the Q tank? Or just dechlorinated tap water with daily 30% changes? I know the filters in the Q tank don't have any bacteria yet.

What about my 75g tank that will be sans fish? How do I tell if it is ready to accept fish? Let it sit for a month? Do multiple water changes? According to my test kits, it was fine, and then everyone died.....

Edit: If I had killed off my seeded bacteria by not having a good enough ammonia source, that means I should have been seeing ammonia and nitrite build up right? Even with 10 fish in the tank for 2 days, I saw nothing.
See less See more
No, I am not using any CO2 or ferts right now. This was going to be run via the non-co2 methods I read about in many of Mr. Barr's postings. I just hadn't gotten around to getting any ferts yet.
I may have misunderstood you, but did you just say that you don't use any water conditioner at all? No removal of chlorine/chloramines?
Oh, I thought by conditioner, something like "Cycle" was meant. I used "Jungle Start Right" as a tap water treatment.
you mentioned a rock, do you know what kind? some rocks like limestone can be very bad. by the way, noticed your location, i live in north strabane.
Small world lol.

It's not a limestone. I am pretty sure it is a large chunck of granite. I also had a very nice gneiss in there. I can't recall if feldspars will break down in water, but I wasn't taking any chances. I am setting them up in a spare tank with nothing but water to see if parameters change.

Where I work we do a lot of environmental sampling, so I submitted my tap water and tank water for analysys. Tomorrow sometime I should know everything there is possible to know about the two of them,from hardness to trace metal concentrations. I hope that will give me some indication of the issue.

In brighter news, my two surviving harlequins seemed to be doing well this morning.
what do you condition your water with?
what he means is how do you remove the chlorine from your tap water?

Read later post.. N/M
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.