How did my fish die?

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

Nekkoriv

Aquarium Advice Apprentice
Joined
Sep 15, 2012
Messages
14
Yesterday I bought phantom tetras for my 20 gallon tank, and I moved my guppies out into their own tank. So I had 5 phantom tetras, a Bolivian ram, and my rainbow shark. I also have a 10 inch plant, and several hiding spots for my fish, including a hut that my rainbow shark claims as it's territory.
When I left for class this morning all of my fish seemed to be doing fine. My rainbow shark was in it's hut, my Bolivian ram was hovering around, and my 5 phantom tetras were swimming in a pack as usual. When I got home (6 hours later) I went to check on m fish, and to my surprise one of my phantom tetras (the biggest) was floating at the top of the tank with no eyes. All of my fish seem to be getting along fine. There have been no signs of aggression since then, and I can't figure out what could have happened. Nothing on my tetra's body was damaged, except for it having no eyes. I now have 3 females, and a male (the tetra that died was male). My water parameters are 6.8 pH, soft water, 0 nitrates, and 0 nitrites. (My kit doesn't test ammonia...).
Did it die, and just get it's eyes eaten after? Was it killed? Should I do a big water change? (My last water change was 30% 8 days ago). If it matters I changed my filter cartridge yesterday right after I put the fish in. Thank you for your time, and help.
 
If you have 0 nitrites and 0 nitrates I'd say your tank isn't cycled and you have ammonia present. How long has the tank been running?
 
I'd agree, having no nitrates in 8 days could mean your not cycled, but I guess if you have a few live plants they could absorb the nitrate. Definitely test for ammonia though, least you could rule it out as a cause
 
If you have 0 nitrites and 0 nitrates I'd say your tank isn't cycled and you have ammonia present. How long has the tank been running?

I don't know how accurate these test strips are. My tank has been running for around 2 months. I've never gotten a nitrate or nitrite reading above 0. And I've tested my water at least 30 times. Also, I've had my rainbow shark and a Bolivian ram in there for about a month and a half. I'm going to hopefully get my water tested at the LFS today.
 
I would get rid of the test strips. Ask your lfs how they test it though. If they test it with strips I wouldn't trust those results either. How long has the tank been set up?
 
I would get rid of the test strips. Ask your lfs how they test it though. If they test it with strips I wouldn't trust those results either. How long has the tank been set up?

2 months. And it's had fish in it for about one and a half. (The rainbow shark and Bolivian ram).
 
I would think you would have some nitrite and nitrate or just nitrate if it is cycled. I would get a test kit that you use drops though and then you will be able to test ammonia as well as the others. It might not be a bad idea to go ahead and do a large pwc in case you do have a high level of ammonia. Just make sure to match the temp. well and use the adequate amount of your water conditioner.

Sorry about your fish though. It is always upsetting.
 
I would think you would have some nitrite and nitrate or just nitrate if it is cycled. I would get a test kit that you use drops though and then you will be able to test ammonia as well as the others. It might not be a bad idea to go ahead and do a large pwc in case you do have a high level of ammonia. Just make sure to match the temp. well and use the adequate amount of your water conditioner.

I just changed my water. I changed about 6 gallons. Should I test the old or new water? I have a sample of both ready to bring to my LFS. I'm assuming old. And, Is changing 25% of the water weekly too much? Should I do less weekly, or the same amount every two weeks instead?
 
I'm no expert on that, but my opinion is pretty much the more clean water the better. The only thing is if the water changes are too large or too often you could stress the fish. What I do for my 20 long is 7/8g every 6-8 days which is roughly 40-45%. It all depends on your stocking too though. If you have a lot of messy fish like plecos you need to change the water more then if you just have tetras or something.
 
I will post the results of my water test tonight when I get back from the LFS. From there we will have a better idea of what the issue is and what I can do to prevent another death.
 
A 50% WC weekly is pretty much standard for many people. It is not too much. If you can afford it investing in an API mater test kit is worth the money. Then you can test your own water and get accurate results when the tests are done properly.

As for the fish, it is upsetting, but as much as I hate to say it sometimes fish just don't acclimate well and sometimes they die for no apparent reason. It could have been overstressed, sick but not showing it visably, or any other number of reasons.

Another thing to consider about your tank is the fact you appear to have had a low bio-load, a shark, a ram, and how many guppies? You state you also have a big plant, what type? You may actually not have any or a very low amount of nitrates if you indeed have a low bio-load, the plant is using the nutrients (nitrate) in the water, and your doing regular WC's. I have a 20L right now with one piece of DW (long branchy type) with several med Java ferns and one anubia on it. There are 4 small juvinelle angels in it. I do my WC's and rarely dose that tank with ferts and when I test it there is usually 0 nitrates. The tank has been set up for way over a year. Yes, your tank is new but that doesn't necessarily mean it's not cycled. Getting water tested with a good liquid reliable test kit will tell you alot IMO.
 
@rivercats I don't have guppies in there anymore. I moved them into their own tank when I put the tetras in the 20 gal. Right now I have a rainbow shark, Bolivian ram, and 4 phantom tetras. And to be honest I don't know what kind of plant it is. It's long, skinny, and 10 inches tall. I bought it at my local Petco.
 
It's hard to say, particularly without an ammonia test. It's possible the fish died and something ate it's eyes after or it could have been attacked. A 20 gal isn't very large for a shark, so as it grows it's going to become territorial and your other fish could be at risk. Sharks can grow rather large as well so you'll be needing a larger tank soon if you want to keep it. At the very least I'd do a 50% water change to clear out any toxins from the dead fish and keep an eye on them, get your own liquid test kit and think about upgrading the tank.
 
@librarygirl I did a 50% just to be safe, and I have plenty of spots for my shark. It's 3 inches already and It is only aggressive to fish that enter it's territory (the hut). But, it only really chases the tetras a little bit, and he leaves the Bolivian Ram alone. I don't really have aggression problems with him. Most likely the one tetra didn't acclimate and they ate it's eyes after it died. I'm going to get the water tested anyway though. Maybe I'll get a liquid test kit too.
 
Back
Top Bottom