Question Who's Eating My Fish!!!

Mizzom

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HI Everyone - I've got a 40G breeder tank in which I have 2 young angelfish, 12 cardinal tetras, 4 female guppies, 5 norman lampeye tetras,1 BN pleco and 4 - cory cats. In the past 2-3 weeks, I took back my female guppies and got a bunch of male guppies because they are so beautiful and I figured the angels would eat the babies anyway, and that would break my heart. When I took the female guppies back, I got about 10-ish male guppies and 3 zebra loaches. One of the loaches died almost immediately and I attributed it to my high PH - around 8-8.5. I went back to the fish store a week later and picked up 5 more cardinal tetras and a bunch more male guppies. I swear I had at least 25-ish guppies in the tank, but didn't count.

So, I noticed a few dead tetras that looked like they had been chewed on which I would expect when a fish dies. However, in the past week and a half, I am down to 4 cardinal tetras, and can account for no more than 4 chewed bodies, one of which I think was a lampeye. Last night when I got home from work, I noticed another chewed up cardinal and one dead guppy that was not chewed on.
I take a good look at my tank and count 4 cardinals left, 3 lampeyes and about 15 guppies. I took everything apart looking for bodies and found that one of the zebras was dead as well as the guppy and cardinal.

I've had the BN pleco for more than a year, so don't think it is responsible for eating the fish, so I/m thinking that the zebra loaches are the culprits? I only have one now, but I think what they were doing was attacking the fish at night when they are on the bottom of the tank sleeping? They are not dying, but are being killed. I monitor/check and water change my water weekly, and it is spot on, just high in ph.
Does anyone have any experience with the zebra loaches being aggressive and eating other fish? I will for sure be taking the remaining zebra loach back to the store and getting more guppies and cardinals.
Sorry this is so long, but wanted to give a complete account on what's going on.
Thanks in advance for your response.
 

bizaliz3

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Sorry you are having trouble.

How do you know the fish are being killed and not just dying first?

You mentioned thinking you lost fish due to PH. But, What are your ammonia, nitrites and nitrates?
 

DuaneV

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Are you testing your parameters? Seems like youve added a LOT of fish all at the same time and Id suspect ammonia & nitrite spikes.
 

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The fact that you found at least one fish (guppy) that was not chewed up would seem to indicate that these fish are dying due to some other cause, and then being scavenged. You find some after they have been dead for awhile, and others, more freshly dead, who bodies have not yet been chewed.

It's hard to imagine that any critter or fish killed a guppy without causing visible trauma to its body in the process. On the other hand, poisoning...i.e. bad water conditions...sounds like a more likely culprit.

The butler did it!
 

NiHa

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First : get rid off the angelfish or quarantine coz angelfish is predator among small fish and if other fish still dead.second : check ur ph and filtration
 

bizaliz3

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NiHa said:
First : get rid off the angelfish or quarantine coz angelfish is predator among small fish and if other fish still dead.second : check ur ph and filtration
That isn't always true. Especially if the Angels grow up with smaller fish. It's not entirely false either though.

The OPs Angels are young though. So they are not the culprit here. And neither is the ph!

I believe its water quality, but that won't be confirmed until the OP responds with those numbers.
 
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Mizzom

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bizaliz3 said:
Sorry you are having trouble.

How do you know the fish are being killed and not just dying first?

You mentioned thinking you lost fish due to PH. But, What are your ammonia, nitrites and nitrates?
jjohnwm said:
The fact that you found at least one fish (guppy) that was not chewed up would seem to indicate that these fish are dying due to some other cause, and then being scavenged. You find some after they have been dead for awhile, and others, more freshly dead, who bodies have not yet been chewed.

It's hard to imagine that any critter or fish killed a guppy without causing visible trauma to its body in the process. On the other hand, poisoning...i.e. bad water conditions...sounds like a more likely culprit.

The butler did it!
I test my water at least once a week and change the water 25-30% every week as well. I am aware that I have added a lot of fish at one time, so was monitoring my ammonia and nitrates often. My ammonia was always 0, and my nitrates were 20. Did not test nitrite. Ph is always high - comes out of the tap that way). I have been trying to lower my ph naturally, and just started recently adding catappa leaves to the tank. Adding one at a time, until I'm up to 4 catappa leaves in the tank with little change in my ph. It's maybe 7.5-8 now. Could that be a problem causing the fish to die? - I don't think so, because it isn't reduced by a lot, and only a little bit, gradually.
Also, for only having four cardinals left out of twelve, 3 lampeyes out of 5, and seems like several guppies are missing, I haven't found that many bodies, it's like where did they go?
I will test my water again tonight after work, and check the nitrites as well and let you know what my parameters are. I changed my water last Friday, and added 2 catappa leaves to the already 2 in the tank. I read that the leaves are also medicinal as well as lowering the ph, but maybe there's something I don't know, as I've never used them before. Thanks for everyone's response, I appreciate it. I'll update my findings tonight after work.
 

bizaliz3

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Mizzom said:
I test my water at least once a week and change the water 25-30% every week as well. I am aware that I have added a lot of fish at one time, so was monitoring my ammonia and nitrates often. My ammonia was always 0, and my nitrates were 20. Did not test nitrite. Ph is always high - comes out of the tap that way). I have been trying to lower my ph naturally, and just started recently adding catappa leaves to the tank. Adding one at a time, until I'm up to 4 catappa leaves in the tank with little change in my ph. It's maybe 7.5-8 now. Could that be a problem causing the fish to die? - I don't think so, because it isn't reduced by a lot, and only a little bit, gradually.
Also, for only having four cardinals left out of twelve, 3 lampeyes out of 5, and seems like several guppies are missing, I haven't found that many bodies, it's like where did they go?
I will test my water again tonight after work, and check the nitrites as well and let you know what my parameters are. I changed my water last Friday, and added 2 catappa leaves to the already 2 in the tank. I read that the leaves are also medicinal as well as lowering the ph, but maybe there's something I don't know, as I've never used them before. Thanks for everyone's response, I appreciate it. I'll update my findings tonight after work.

Ya let us know about the readings tonight.
What you are describing does not sound like fish are being murdered one after another. Not with the stock you have. So we've gotta figure out another explanation.

How long has the tank been running? How long have you had all the fish? How big are the Angels?
 
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bizaliz3 said:
That isn't always true. Especially if the Angels grow up with smaller fish. It's not entirely false either though.

The OPs Angels are young though. So they are not the culprit here. And neither is the ph!

I believe its water quality, but that won't be confirmed until the OP responds with those numbers.
I am almost positive it is not the angels, as they are young juveniles and have been in the tank for several months. Their mouths aren't big enough, and I've not seen any aggressive behavior at all between them and the other fish. In my last tank I had an angelfish that grew to be humungous, so I gave it to my son to put in his 125. He never went after the smaller fish. I also doubt it is my ph, as I read that guppies and angels do well in high ph. My corys and cardinals also did well in my larger tank. I would be blown away if it is indeed my water, as I'm very on top of my water every week - but I will check it and report my findings tonight to let you know. Thanks again.
 

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I don't think that your efforts to change pH would have such a drastic and immediate effect that it would cause fish deaths...but I still think it's in the water.

I don't know how big your Bristlenose is, but between him working over a carcass and the other fish pitching in to help, it seems possible that some of these dead fish (all of which are small) could simply disappear before you found them. You've found them in every other stage of disrepair, ranging from intact (freshly dead) to somewhat chewed up (dead a bit longer); it could be that the next stage would be completely gone (dead for a day or so, and "et right up").
 
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bizaliz3 said:
Ya let us know about the readings tonight.
What you are describing does not sound like fish are being murdered one after another. Not with the stock you have. So we've gotta figure out another explanation.

How long has the tank been running? How long have you had all the fish? How big are the Angels?
This tank has been up and running for about 6 months. My BN is from my other tank I had running for two years. All other fish are from the new start up tank six months ago. Angels are not tiny babies, I'd call them juveniles. I've had them about three months. I had about 7 cardinals and 3-4 female guppies for about 4 months with no problems. I took the female guppies back and got a bunch of male guppies and 5 more cardinals and two zebra loaches. My corys are about three months in the tank - they are doing well. NONE of my fish look or act ill, I check daily for anything out of the ordinary. I know that doesn't mean anything can't happen, just thought I'd mention it. In the beginning of my startup, I had trouble controlling my nitrates, but it seems to be balanced out now. When the nitrates were high, I didn't have any fish deaths. I vacuum "most" of the gravel every week (leaving a few spots where I have plants undisturbed) and I change out my white polishing pads every week with my water change. I have two AquaClear 70 filters on my tank. Since I started changing out the polishing pads every week (they are really dirty), my nitrates are much better - last test was 20ppm - best ever.
Let me know if there is something else I didn't mention. (I gotta get back to work now) Will report my findings tonight. Thank You Everyone!
 
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water test.jpg fish tank pic.jpg
Okay - Here are my test results and a pic of my tank. Using a test strip, my GH is 30, and KH is 120. I did not have any fish deaths today. My temp runs at around 77.5.
I looked, and actually have more guppies than I thought I did, they are just more spread out now that they are used to their surroundings. I have around 15-20. All fish are acting well.
I checked my BN pleco too, and he is about 4 inches long and looks very healthy. I've had him about 1-1/2 -2 years.
So now I'm not sure if I should keep the one remaining zebra loach. Even if he isn't responsible for killing the fish, I don't want him to be unhappy being the only loach. I wonder why my other zebra loach died. He was fine the night before, and then dead yesterday when I came home from work. People at the fish stores say that my ph is a little too high for them, do you guys think so?
 

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2 young angelfish,
12 cardinal tetras
5 norman lampeye tetras
1 BN pleco
4 - cory cats.
25-ish guppies

In a 40 gallon tank?

I'm going with the fish died because poor water conditions due to overstocking and were chewed on by their tank mates, Plecos love eating dead fish.
 

NiHa

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Mizzom said:
water test.jpg fish tank pic.jpg
Okay - Here are my test results and a pic of my tank. Using a test strip, my GH is 30, and KH is 120. I did not have any fish deaths today. My temp runs at around 77.5.
I looked, and actually have more guppies than I thought I did, they are just more spread out now that they are used to their surroundings. I have around 15-20. All fish are acting well.
I checked my BN pleco too, and he is about 4 inches long and looks very healthy. I've had him about 1-1/2 -2 years.
So now I'm not sure if I should keep the one remaining zebra loach. Even if he isn't responsible for killing the fish, I don't want him to be unhappy being the only loach. I wonder why my other zebra loach died. He was fine the night before, and then dead yesterday when I came home from work. People at the fish stores say that my ph is a little too high for them, do you guys think so?
Ph and filtration not good although its clear water when I saw ur aquarium
 

bizaliz3

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Hmm. Well the water quality looks good anyway based on the test! So that's good!

Beautiful tank!
 
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NickAu said:
2 young angelfish,
12 cardinal tetras
5 norman lampeye tetras
1 BN pleco
4 - cory cats.
25-ish guppies

In a 40 gallon tank?

I'm going with the fish died because poor water conditions due to overstocking and were chewed on by their tank mates, Plecos love eating dead fish.
I'm no expert, that's for sure, but most of my fish are small, therefore have a smaller bio load. I have two AC 70 filters that filter 600 gallons per hour, and if my 40 gallon breeder tank turned over 10 times, that would only be 400 gallons. I also change my water every week without fail. Do you really think I have poor water conditions? Maybe I'm not doing the math right. Is my bio load too much that even the two filters couldn't filter the tank adequately? I did have a AC 110 on there with a 70, but the water flow was way too much for the tank? I do agree that the pleco could very well be eating the dead fish. I was 'assuming' that they were being attached by the zebra loaches at night while they were low and sleeping, but I could be totally wrong. Guess I'll never know.

bizaliz3 said:
Hmm. Well the water quality looks good anyway based on the test! So that's good!

Beautiful tank!
Thanks! It truly is a labor of love, as I am sure it is for all of you. They are my babies, and I want them all to be happy and healthy.
 

bizaliz3

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Mizzom said:
Thanks! It truly is a labor of love, as I am sure it is for all of you. They are my babies, and I want them all to be happy and healthy.
You do have a lot of fish in there, but it's not grossly overcrowded...you are well filtered and clearly on top of the maintenance as the results of your tests prove! So you're doing just fine! Hopefully you have no further losses. :)
 

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Your pH is high, and the water is hard. Are the fish you buy in similar water in the shop? If they’re not and you’re not acclimating them slowly enough the culprit could be pH shock or osmotic shock. Both can take a few days or weeks to kill.

Angels can be fine with small fish and yet eat any new additions of the same species, although they’re not the culprit either. They don’t ‘chew fish over’ they swallow them. And the BN can easily make a dead fish disappear overnight...
 
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bizaliz3 said:
You do have a lot of fish in there, but it's not grossly overcrowded...you are well filtered and clearly on top of the maintenance as the results of your tests prove! So you're doing just fine! Hopefully you have no further losses.
Thanks. I won't be adding any more fish.
 

NickAu

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Hi

tank turned over 10 times, that would only be 400 gallons.
That is not quite correct.

Filtration and turnover rate are 2 different things, In fact too much turnover/flow rate can mean your filter is not working efficiently because the water is flowing too fast over the media.
 

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