New Aquarium: Mystified By Fatalities

HI there,

I'm a fairly experienced aquarist (I've kept a 65g planted freshwater tank and 120 gallon saltwater setup before), but I've been out of the hobby for awhile. I recently started a new planted 55 gallon aquarium and I've killed about half the fish I've put into it. I don't really think I've fixed the situation, and I'm very keen for ideas.

On 7/1, I set up the aquarium (substrate, plants) and ran it on a fishless cycle for 19 days. Using API test kits, I monitored the pH, ammonia, nitrite, and nitrate. When the cycle had run its course and water conditions were perfect, on 7/20, I added four cory catfish and eight cardinal tetras. Water conditions were 79*F, pH 7.8, Ammonia 0ppm, Nitrite 0ppm, Nitrate 0ppm. Initially, everything went great. The fish were happy and eating.

On 7/25, I was starting to lose fish. I recognize that I probably added a few too many fish and maybe started an additional mini-cycle. I added prime. I changed some water. But my test results still showed the water conditions as very good.

On 7/27, really worried, I did a 60% water change (even though my readings are still good). I took some water to a LFS, got some confusing advice, lowered the pH to 7.0 (under the theory that maybe 7.6 was too high, and certainly ammonia is more lethal at higher pH). I added Cycle too.

7/28, I've killed about half of the fish.

7/29, problem is unchanged. 79.6*F, pH 7.0, Ammonia 0ppm, Nitrite 0ppm, Nitrate 0ppm.

I'm starting to wonder if, perhaps, there is an additional source of toxicity in the aquarium. I've been quite careful, but there are two pieces of wood in the tank, purchased from the LFS. I did nothing in particular to them (no boiling, no soaking). One, I noticed, got some odd algae growth on it, while the other did not. The cories immediately attacked this algae. I just regarded it as the normal growth of a planted tank where this a lot of light and not yet that many plants.

Any other ideas? Please help! I really appreciate your assistance.

MM

 

During your fishless cycle, did you add an ammonia source to the tank?

 

During your fishless cycle, did you add an ammonia source to the tank?

Fahn, yes. There was plant material in there as well as substrate that advertised itself as having biological material as well as the helpful bacteria. Using the test kits, I watched ammonia rise and fall, then nitrite rise and fall. (I kind of like doing the tests.) It was a text book cycle, though the ammonia and nitrite readings never went very high.

 

A properly cycled tank of that size should have easily handled that bioload, so I really don't think overstocking was your issue, especially if you never registered an ammonia spike with your tests.

 

A properly cycled tank of that size should have easily handled that bioload, so I really don't think overstocking was your issue, especially if you never registered an ammonia spike with your tests.

Riffranger, thanks, that was my intuition, too. I did get one test that registered 0.25ppm Ammonia. It was a plant that didn't take. I pulled it out and the tank back down to 0ppm. But the fish are not improving.

 

Fahn, yes. There was plant material in there as well as substrate that advertised itself as having biological material as well as the helpful bacteria. Using the test kits, I watched ammonia rise and fall, then nitrite rise and fall. (I kind of like doing the tests.) It was a text book cycle, though the ammonia and nitrite readings never went very high.

May I ask which substrate you used?

 

May I ask which substrate you used?

Of course ... I set up the tank on 7/1. Realizing the substrate was not deep enough, I re-did the tank on 7/5.

I used 60lbs of Carib Sea Eco-Complete, 20lbs of Seachem Flourite and then 40lbs of type of biologically neutral aquarium gravel on top (can't remember the brand). Substrate is about 3-4" thick.

 

What are the deaths like?
Normal behavior and then suddenly gone? Or symptoms first?
Anything noteworthy on the body after you retrieve it?

 

What are the deaths like?
Normal behavior and then suddenly gone? Or symptoms first?
Anything noteworthy on the body after you retrieve it?

Thanks, GettinTanked. The fish have died one-by-one. The cories, which were at first very active, go very still, just sitting on the bottom. They occasionally do their characteristic up-to-the-top-of-the-tank move, but they seem off balance, and get caught in leaves. Their eyes seem to turn red. They show signs of stress. They turn up dead in the morning. Two of four have died.

The tetras initially swam all about the tank and played in the current. When "the problem" set in, they withdrew to the corner, stopped eating, and showed signs of stress. Their colors are still good. They just turn up dead in the morning. About four of eight have died.

I've seen no obvious sign of disease, however.

 

Thanks, GettinTanked. The fish have died one-by-one. The cories, which were at first very active, go very still, just sitting on the bottom. They occasionally do their characteristic up-to-the-top-of-the-tank move, but they seem off balance, and get caught in leaves. Their eyes seem to turn red. They show signs of stress. They turn up dead in the morning. Two of four have died.

The tetras initially swam all about the tank and played in the current. When "the problem" set in, they withdrew to the corner, stopped eating, and showed signs of stress. Their colors are still good. They just turn up dead in the morning. About four of eight have died.

I've seen no obvious sign of disease, however.

It sounds like you you've done everything right, so I'm really grasping at straws here to think of what could be going wrong...
Starting from the top:
You wiped out the tank when you got it and removed all labels and adhesive, I'm sure.
How much do you trust this fish store?
Yes, both your pH and temp are slightly higher than the suggested range for most cory species and the cardinal tetra, but advising you to change your pH that drastically probably did more harm than good. Did you ask what parameters the fish are held in at the store? Presumably similar, if it's nearby.
Did you slowly acclimate the fish when you brought them home?
Do you know the hardness of your water?
Gravel isn't the best substrate for corys, particularly if it has sharp edges. But it shouldn't have caused deaths so quickly. 4 inches is also probably the maximum depth you would want your substrate to be to avoid sulfurous compounds forming in it. But it's pretty early on for enough waste to have accumulated beneath it for that to be an issue.
It is normal for wood to slough as yours did for a while. The one that's not sloughing is more curious- do you know what type it is?

You see these cases of knowledgeable fish keepers having deaths a lot. And so many fish are farmed under conditions where they contract disease now. I can't help but wonder if some fish stores medicate their water to keep fish alive, and then they just die when you buy them in the absence of that medication. Sounds expensive though.
You don't have to answer these questions, of course, just throwing out ideas that might help you piece together what's going on.

 

It sounds like you you've done everything right, so I'm really grasping at straws here to think of what could be going wrong...
Starting from the top:
You wiped out the tank when you got it and removed all labels and adhesive, I'm sure.
How much do you trust this fish store?
Yes, both your pH and temp are slightly higher than the suggested range for most cory species and the cardinal tetra, but advising you to change your pH that drastically probably did more harm than good. Did you ask what parameters the fish are held in at the store? Presumably similar, if it's nearby.
Did you slowly acclimate the fish when you brought them home?
Do you know the hardness of your water?
Gravel isn't the best substrate for corys, particularly if it has sharp edges. But it shouldn't have caused deaths so quickly. 4 inches is also probably the maximum depth you would want your substrate to be to avoid sulfurous compounds forming in it. But it's pretty early on for enough waste to have accumulated beneath it for that to be an issue.
It is normal for wood to slough as yours did for a while. The one that's not sloughing is more curious- do you know what type it is?

You see these cases of knowledgeable fish keepers having deaths a lot. And so many fish are farmed under conditions where they contract disease now. I can't help but wonder if some fish stores medicate their water to keep fish alive, and then they just die when you buy them in the absence of that medication. Sounds expensive though.
You don't have to answer these questions, of course, just throwing out ideas that might help you piece together what's going on.

No, I really appreciate the questions and spit-balling ideas. I've never been in quite this situation before. Certainly, I've killed a few fish over the years, but not in this type situation. And I felt like I set up the tank so methodically. I too am grasping at straws.

Yes, I cleaned the tank out when I got it.

The LFS seems like a rather good one. The fish came from LiveAquaria, however. It was my first time getting fish like that, but they certainly seemed to arrive in good condition. As for advice from the LFS, well, it's been mixed. They asserted that my pH was too low ... I bought three different test kits and confirmed, via all three, that my pH was 7.6 not 6.0 as they asserted. Not sure how to account for that.

My understanding is that the fish at LiveAquaria are kept at a pH of around 7.6, too. My tap water comes out about there, so I was hoping to use water at that pH. I know it's a little high for tetras. Perhaps dropping the pH to 7.0 was a bad idea ... But it's done, and it did not seem to worsen the situation.

I'm letting the temp drop a few degrees.

Yes, I acclimated them carefully, and they seemed to do well at first.

My water is hard, 7.4 grains per gallon, according to the city's water report. I don't yet have a test kit for that.

The gravel is rounded and small. I don't think it could be harming the cories. I deliberately made it the current depth for plants. I can't imagine there's much waste there yet.

I'm glad to hear that it's normal for the wood to slough. Both pieces came from the same bin at the LFS and look similar, but I don't really know what they are. See picture.

 

Are you cleaning it regularly?
Washing hands thoroughly before tiring them in tank?
Acclimating fish before putting them in/not mixing water from bag into tank?

I’ve had a few mystery deaths like that before , I hope you figure it out

 

Are you cleaning it regularly?
Washing hands thoroughly before tiring them in tank?
Acclimating fish before putting them in/not mixing water from bag into tank?

I’ve had a few mystery deaths like that before , I hope you figure it out

Thanks, Ian.

Yes, I usually wash my hands before putting them in the tank (just tap water, no soap). I wouldn't say I always do that 100% of the time, however. I will be more conscious of that.

I've been changing A LOT of water ...30% on Wednesday evening, when I returned from a work trip, then 60% Friday morning. I'd change more if I thought it would help.

Yes, I acclimate them well and tried to keep water from the bag from getting into my system. Maybe a little did, but it wasn't much.

 

No, I really appreciate the questions and spit-balling ideas. I've never been in quite this situation before. Certainly, I've killed a few fish over the years, but not in this type situation. And I felt like I set up the tank so methodically. I too am grasping at straws.

Yes, I cleaned the tank out when I got it.

The LFS seems like a rather good one. The fish came from LiveAquaria, however. It was my first time getting fish like that, but they certainly seemed to arrive in good condition. As for advice from the LFS, well, it's been mixed. They asserted that my pH was too low ... I bought three different test kits and confirmed, via all three, that my pH was 7.6 not 6.0 as they asserted. Not sure how to account for that.

My understanding is that the fish at LiveAquaria are kept at a pH of around 7.6, too. My tap water comes out about there, so I was hoping to use water at that pH. I know it's a little high for tetras. Perhaps dropping the pH to 7.0 was a bad idea ... But it's done, and it did not seem to worsen the situation.

I'm letting the temp drop a few degrees.

Yes, I acclimated them carefully, and they seemed to do well at first.

My water is hard, 7.4 grains per gallon, according to the city's water report. I don't yet have a test kit for that.

The gravel is rounded and small. I don't think it could be harming the cories. I deliberately made it the current depth for plants. I can't imagine there's much waste there yet.

I'm glad to hear that it's normal for the wood to slough. Both pieces came from the same bin at the LFS and look similar, but I don't really know what they are. See picture.

View attachment 461082

Beautiful tank.
Are you dosing CO2? On what schedule?

 

Beautiful tank.
Are you dosing CO2? On what schedule?

Thank you!!! (If only it weren't lethal for the fish.)

No, not yet. I am planning to add CO2, but I'm going on vacation in August and figured I'd set that system up when I return. I was also curious to see how the plants grew in without CO2.

 

Ammonia 0ppm, Nitrite 0ppm, Nitrate 0ppm.

MM

Hi

Sorry you're having troubles. I do love your tank, it looks great!

I'm a little concerned that your nitrates were at 0. What do they read now?

 

Hi

Sorry you're having troubles. I do love your tank, it looks great!

I'm a little concerned that your nitrates were at 0. What do they read now?

This is confusing me, as well. 0 nitrates suggests the tank isn't cycled properly but she also isn't seeing ammonia despite still having fish.

 

This is confusing me, as well. 0 nitrates suggests the tank isn't cycled properly but she also isn't seeing ammonia despite still having fish.

I just re-tested Nitrate. It is definitely at or near zero, now. Around 7/12-7/18, the Nitrate level spiked up to about 5ppm.

Friday morning, I changed out about 60% of my tank water.

 

I'm still very new to this hobby, I had no idea there was a substrate that would cycle a tank.

 

This is confusing me, as well. 0 nitrates suggests the tank isn't cycled properly but she also isn't seeing ammonia despite still having fish.

It's a big, new tank with only 6 small fish and lots of plants. Nitrates could certainly be near 0.

 

I'm still very new to this hobby, I had no idea there was a substrate that would cycle a tank.

Well, maybe it wasn't the best idea ... From the substrate and the plants (some dying leaves), there was definitely some ammonia entering the system. The ammonia level rose to about 0.5 ppm (7/7), then nitrite at 0.5 ppm (7/10), and nitrate at 5ppm (7/13).

But maybe this cycle was too gentle to get adequate bacteria growth? I did have someone at the LFS cast doubt on the idea of a fishless cycle.

 

From what I've read here and elsewhere most people doing a fishless cycle will dose the tank to between 2 and 4 ppm ammonia and refresh/maintain that as needed until the tank will cycle it to 0 ammonia and whatever resulting nitrates in under 24 hours.

 

From what I've read here and elsewhere most people doing a fishless cycle will dose the tank to between 2 and 4 ppm ammonia and refresh/maintain that as needed until the tank will cycle it to 0 ammonia and whatever resulting nitrates in under 24 hours.

I've never myself directly dosed ammonia into a fishless system.

I'm reading some of those other accounts, too. Their numbers have gotten much higher than mine.

In a positive development, as the lights came up on my tank, the fish are acting more normal. It would make me happy if the tetras ate.

 

Well, maybe it wasn't the best idea ... From the substrate and the plants (some dying leaves), there was definitely some ammonia entering the system. The ammonia level rose to about 0.5 ppm (7/7), then nitrite at 0.5 ppm (7/10), and nitrate at 5ppm (7/13).

But maybe this cycle was too gentle to get adequate bacteria growth? I did have someone at the LFS cast doubt on the idea of a fishless cycle.

They were probably just trying to sell you some fish...
You test the water often and don't see ammonia or nitrite, so there's a cycle going. Maybe not a strong one, because there isn't a great deal of ammonia being produced, but it should be enough for slowly adding fish.

It seems like the possibilities are: disease or contaminant.
If something in the tank was contaminated somehow, it should leach into the water and over time be removed by water changes. This shouldn't take long if it was something like a surface cleaner that got in there. Deaths should lessen quickly. If it's something like metals in your rocks (I've read this is a thing, but someone please correct me if I'm wrong), that would be a problem that could persist for longer. Are your rocks from the LFS? Another contaminant that could be problematic long term would be if the wood were of an undesirable sort. It looks pretty aquarium safe, but maybe try to ID it just in case.

The symptoms are so vague, it probably wouldn't be wise to medicate. (Though I would be tempted to dose Paraguard) Stress coat couldn't hurt the situation though. I would sit with the fish you have now, do your water changes, see if the deaths come to a halt.

 

They were probably just trying to sell you some fish...
You test the water often and don't see ammonia or nitrite, so there's a cycle going. Maybe not a strong one, because there isn't a great deal of ammonia being produced, but it should be enough for slowly adding fish.

It seems like the possibilities are: disease or contaminant.
If something in the tank was contaminated somehow, it should leach into the water and over time be removed by water changes. This shouldn't take long if it was something like a surface cleaner that got in there. Deaths should lessen quickly. If it's something like metals in your rocks (I've read this is a thing, but someone please correct me if I'm wrong), that would be a problem that could persist for longer. Are your rocks from the LFS? Another contaminant that could be problematic long term would be if the wood were of an undesirable sort. It looks pretty aquarium safe, but maybe try to ID it just in case.

The symptoms are so vague, it probably wouldn't be wise to medicate. (Though I would be tempted to dose Paraguard) Stress coat couldn't hurt the situation though. I would sit with the fish you have now, do your water changes, see if the deaths come to a halt.

OK ... Thanks for your thoughtful response.

Yes, the rocks came from the same LFS. I did not write down the exact type.

I'll grab some Paraguard and Stress Coat and see if that helps.

I am hopeful that the situation is improving and, with luck, the tetras will eat tonight.

 

OK ... Thanks for your thoughtful response.

Yes, the rocks came from the same LFS. I did not write down the exact type.

I'll grab some Paraguard and Stress Coat and see if that helps.

I am hopeful that the situation is improving and, with luck, the tetras will eat tonight.

If you go to the LFS for those items, check out the tanks of the fish that you bought. See if they look well. If they do look well, I'd be more swayed to try just dosing the Stress Coat. If they don't, I'd be more inclined to dose the Paraguard. If they happen to have symptoms that point to a particular illness, you could use the medication for that instead. For instance, if let's say you look in and you see some cardinals listing at the surface with long stringy poop. Now you have evidence to believe it's more likely a parasite and you should get General Cure or Prazipro instead (Paraguard is better for external illness). The shock of a new environment may have compromised your fish's immune system, causing them to die much faster from something they were already inflicted with. Meanwhile, the fish at the store have had a consistent environment and are fighting the disease more slowly, giving them time to develop visible symptoms.
Maybe ask them what kind of rocks and wood you got too, then look them up online and see if it seems right.

I hope things turn around for you soon. Good luck!

 

Suffered identical problems myself with similar deaths, at same water perameters. The killer was the hardness. Get a KH/PH test kit and the Seachem Acid regulstor, and get the hardness down and I think you might solve the problem.
critterkeeper

 

Suffered identical problems myself with similar deaths, at same water perameters. The killer was the hardness. Get a KH/PH test kit and the Seachem Acid regulstor, and get the hardness down and I think you might solve the problem.
critterkeeper

Critterkeeper, thanks! You may be right. I'm going to order the things you suggest. ASAP.

Just an update. The deaths stabilized during the week. My water tests continue to be good. Then, I added a few neon tetras on Friday. They were all belly up this evening. A few fish seem to be doing okay ... maybe they're just able to handle the hardness better.

Thanks for your idea.

MM