7 Fish Gone in a Week!

[Sasha]

What's going on with my 29 gallon tank! During the past week I have lost a total of 7 fish! My 5 black mollies and 2 guppies have died for no apperent reason. I reallly need to figure out what's been killing my fish. Everyday, I found another one dead and still have no clue what's happening. The fish showed no signs of stress, no parasites and no wounds. They were eating normally and they seemed to all die only at night.

Now, a little information about that tank. The 29 gallon aquarium has been established for over a year. I have a high capacity filter that's an Aquacler 200. The temperature is maintained around 78 degrees and the heater is working fine. I tested everything about the water (even brought a sample to Petco so they could test it) and it was all perfect. I clean the filter once a week and rinse one sponge with the aquarium water and do a 20% water change. I add salt into the new water and water conditioner.

Sadly, two of my other fish are acting strange now and I fearing that they would be the next victim to die. I have a 46 gallon tank that'a almost finished cycling, so my other option to to transport the fish in there, but I don't know if that would help. Any advice of why my fish are dying? What's wrong with my 29 gallon tank?

Sorry if it's a little long, but I have to explain everything. Any suggestions welcome!

 

[FrankSlapperinni]

Did you add any chemicals or medications recently? what are your ammonia and nitrite levels?

 

[Sasha]

I haven't added any medications. I have a hospital tank availabe with an air pump and heater.

Ammonia is at 0
Nirite is at 0

Any advice? No one seems to know what's wrong!

 

[phoenix]

I assume you are adding a dechlorinator when adding water right?

 

[Sasha]

I add water dechlorinator whenever I add new water and aquaium salt. I have no idea what's killing my fish!

 

[phoenix]

ok another question how much salt do you add/have you added? I dont think salt dissapears from the tank is it possible you have to high of a salt content?

 

[Sasha]

I only add aquarium salt when I change the water. The package saids 1 rounded tablespoon for every 5 gallons. I change 20% of the water every week and add one tablespoon of salt. I'm still puzzled of what is causing my fish to die!

 

[guppygirl]

Are you sure It's not the tempature? That sounds like tempature fluctuation to me.

 

[Changes-In-Latitude]

The first thing that struck me was the fact that 5 of the black mollies died. Is the 29 gallon tank stock list you have in your sig the same tank?
Curious I looked around abit and found some info on black mollies in particular.
They require a pH of about 7.8, need medium to high alkalinity, and require a temp of 80 to 82. It appears that black mollies can be very sensitive to these requirements.
Just thought I'd post up what I read with the hope that this info might help your very puzzling problem.

 

[Sasha]

The 29 gallon is on my signature. I have no idea what the probelm is. I just lost another black molly and a balloon mollt this morning. In he past 9 days, I have lost 9 fish! This is too tragic!

 

[Changes-In-Latitude]

With the addition of salt with every water change in addition to whats already in your water out of the tap it's possible that the level of dissolved solids is to high. You can get this checked with a TDS (Total Dissolved Solids) meter.

Also salinity affects oxygen content in the water. When you check the tank in the morning are the fish gasping near the surface?

This is definately a puzzling problem and I hope you can get it solved.

 

[LoveMyOscar]

 

[Sasha]

The fish were not gasping at the suface. Sadly, I hardly have any fish that swim at the top of tha tank. My tank looks so empty! One day the fish are doing fine and a day later they are dead on the bottom.

Nirates are at 25 mg/l. I'll have to do a water change to bring them down. Are Nitrates deadly to fish?

I brought a water sample to Petco so they could test it and maybe give me some suggestions. The water tested out perfectly and the employee said she has no idea what's going on with my tank because they never heard of anything like this. I don't know who else to ask because nobody has any answers. Last month I started out with 16 fish...now I'm down to to 8 fish. Please help me solve this unknown crisis!

 

[LoveMyOscar]

 

[st.cichlid]

internal parisites,or gill flukes