My corydoras are dying :(

[Woody781]

earlier this week I noticed 2 of my peppered corydoras have died. I do have a testing kit and I did test the water and the ammonia was up a little. So I decided to do a water change, did that. Then I took some of the water I had in the tank before water change to the pet shop to see what the problem was on Thursday. They said the ammonia was up too -was the same reading as I got. They told me to put 1ml of prime in every day for the next 5 days in a 34L tank so I have been doing that because I didnt know what else to do. They also said the ammonia could be to do with the dead fish if I hadn't spotted it for a little bit.

The only change I can think of is I put two new plants in on Sunday 2weeks ago. The plants are blue stricta and giant cardamine (that plant is dying already), could this be the problem?

Unfortunately I came home today and another one is dead!! I only have one more and he's probably freaking out that his mates are gone. I took him out of the tank into a bucket because maybe the plants are the problem. What do you think?

 

[Woody781]

Here's some pictures of the plants in my tank and my last corydoras

 

[fluttermoth]

If you have any trace of ammonia in the water, you need to do a large water change to bring it down.

Even small amounts of ammonia can be fatal to fish; anything over 0.25ppm is a problem.

How long has your tank been running? How are you maintaining the filter? Exactly what fish do you have? Can you post the actual numbers from all the tests you've done, please?

I have to say, your tank is very small; too small for proper shoals of cories and neons anyway; you should think about getting something a bit bigger if at all possible.

 

[Woody781]

If you have any trace of ammonia in the water, you need to do a large water change to bring it down.

Even small amounts of ammonia can be fatal to fish; anything over 0.25ppm is a problem.

How long has your tank been running? How are you maintaining the filter? Exactly what fish do you have? Can you post the actual numbers from all the tests you've done, please?

I have to say, your tank is very small; too small for proper shoals of cories and neons anyway; you should think about getting something a bit bigger if at all possible.

I have had my tank running for about 9 months. I had 4 corydoras and about 10 or 11 neon tetras. I do have a new tank but I'm trying to locate a new light for it and it's proving to be difficult! My new one is 90L but it's not set up or cycled yet.

What do you mean by how am I maintaining the filter?? I do water changes once a week. I will post numbers tomorrow as its 11pm here and I'm about to go to sleep.

 

[Woody781]

If you have any trace of ammonia in the water, you need to do a large water change to bring it down.

Even small amounts of ammonia can be fatal to fish; anything over 0.25ppm is a problem.

Even though I'm a novice I do know this and I did a big water change when I found the first lot of dead fish. I forgot to mention I did do another water change yesterday as well

 

[fluttermoth]

I hadn't noticed you were in Australia, I'm so sorry! Tomorrow's fine, of course!

The reason I ask about the filter is that sometimes we find people are cleaning it out under the tap, or replacing the media too often, which means their tanks never cycle, so I had to check

If I were you, I'd consider moving to the larger tank ASAP; it will be much easier for you to keep stable. Fish actually don't need a light in their tank at all; they can manage with just the ambient light from the room, as can some of the hardier, low light plants, like Java fern and anubias.

In the meantime, keep all the fish in the tank, and do daily water changes; there could always be something we can't or don't test for present and, in any case, if you have any ammonia, water changes are the best, easiest way to keep the fish safe.

I doubt it's the plants that are causing the problem, but anything dead can cause ammonia, and in such a small volume of water, things can spiral out of control very quickly; best remove them if you think they're dying, rather than move the fish.

Hope things improve; good luck and let us know how things are tomorrow x

 

[seangee]

Its worth checking out http://aqadvisor.com/AqAdvisor.php. According to that 4 corys is already overstocked without the tetra.

FWIW Corydoras should be on a sand substrate as their barbels are easily damaged and can get infection from rooting around in gravel. Mentioning that because when you are overstocked a single dead fish could be sufficient to cause the ammonia spike, even if it died of something else.

As Fluttermoth says: Try to move them ASAP. If possible put your old filter in there, alongside the new one as it will help with the cycle.

 

[Crispin]

You mentioned that you added plants a couple of weeks prior to losing the Corydoras. Were the plants sourced from a reputable shrimp and snail safe dealer? I ask as sometimes plants are treated with chemicals like copper or insecticides to kill off any hitch hikers. Years ago I fell foul of this when I purchased plants off of an eBay seller, placed them into my tank and wiped out all of my snails and shrimp. I remember this well because I started losing fish as well and it was my catfish that were worst effected

Another potential issue you may have is your substrate. Ideally Corydoras should be kept with a fine sand substrate. They spend a lot of their time digging into and sifting through the sand looking for food. I imagine if they were unable to do this it could lead to them becoming stressed out, I've also been led to believe that gravel can wear down and injure their barbels to the point they're no longer able to eat or they become susceptible to bacterial and fungal infections.

As for the ammonia levels, the best course of action is of course large water changes. I wouldn't rely on adding chemicals like Prime alone to 'detoxify' ammonia. I've certainly never trusted that method; Seachem themselves are very vague on what is happening to the ammonia and how it actually rendered non-harmful. Do as many water changes as it takes to keep the levels down and perhaps consider feeding less in the meantime. This will help ensure total ammonia production is kept as low as possible as your tank cycles. I would try and pinpoint what caused the elevated ammonia levels. An unnoticed fish death could of course explain this, but there could be other culprits like a clogged filter, excessive detritus in the tank etc..

 

[Woody781]

I hadn't noticed you were in Australia, I'm so sorry! Tomorrow's fine, of course!

The reason I ask about the filter is that sometimes we find people are cleaning it out under the tap, or replacing the media too often, which means their tanks never cycle, so I had to check

If I were you, I'd consider moving to the larger tank ASAP; it will be much easier for you to keep stable. Fish actually don't need a light in their tank at all; they can manage with just the ambient light from the room, as can some of the hardier, low light plants, like Java fern and anubias.

In the meantime, keep all the fish in the tank, and do daily water changes; there could always be something we can't or don't test for present and, in any case, if you have any ammonia, water changes are the best, easiest way to keep the fish safe.

I doubt it's the plants that are causing the problem, but anything dead can cause ammonia, and in such a small volume of water, things can spiral out of control very quickly; best remove them if you think they're dying, rather than move the fish.

Hope things improve; good luck and let us know how things are tomorrow x

I haven't learnt yet how to split up the quotes so I'll just answer by different paragraphs.

With the filter actually media I hardly ever touch it. Sometimes when I'm doing a water change I wash the media in the water I take out of the tank and I did do this when the first 2 fish died because it just looked a little yuck. With the wool I dont often change that either because I have been reading and getting advice on here that you don't need to change it so much but I have done that just after I got the new plants and 1/2 of its brown already.

When the fish died I also put in some carbon wool hopefully to help my fishes situation. I know it only lasts for a week but it can't harm them. Also I clean the pipe that lets out the water into the tank under the tap as it needs a bit of pressure but rinse it in the water change dirty tank water before putting it back in -this does get a bit clogged from time to time.

I also know fish don't really need the light of the tank but my plants do. I have Anubias and Blue Sticta -I took out that other plant because it was dying anyway. Are you saying that Anubias don't really need the tank light?

I've always wanted different plants in my tank. I had one when I first set up my tank called, well can't remember what it was called but it was a soft fluffy looking branches but I couldn't keep it alive. The point of the matter is that I do want to have different heights and maybe different types of plants in my tank.

Could a lone fighter fish live in my 34L tank? I was planning to get the 90L cycled and move the fish over to it when ready then put a fighter in the 34L tank.

I did another water change this morning. You said do daily water changes, 25%?

 

[Woody781]

You mentioned that you added plants a couple of weeks prior to losing the Corydoras. Were the plants sourced from a reputable shrimp and snail safe dealer? I ask as sometimes plants are treated with chemicals like copper or insecticides to kill off any hitch hikers. Years ago I fell foul of this when I purchased plants off of an eBay seller, placed them into my tank and wiped out all of my snails and shrimp. I remember this well because I started losing fish as well and it was my catfish that were worst effected

Another potential issue you may have is your substrate. Ideally Corydoras should be kept with a fine sand substrate. They spend a lot of their time digging into and sifting through the sand looking for food. I imagine if they were unable to do this it could lead to them becoming stressed out, I've also been led to believe that gravel can wear down and injure their barbels to the point they're no longer able to eat or they become susceptible to bacterial and fungal infections.

As for the ammonia levels, the best course of action is of course large water changes. I wouldn't rely on adding chemicals like Prime alone to 'detoxify' ammonia. I've certainly never trusted that method; Seachem themselves are very vague on what is happening to the ammonia and how it actually rendered non-harmful. Do as many water changes as it takes to keep the levels down and perhaps consider feeding less in the meantime. This will help ensure total ammonia production is kept as low as possible as your tank cycles. I would try and pinpoint what caused the elevated ammonia levels. An unnoticed fish death could of course explain this, but there could be other culprits like a clogged filter, excessive detritus in the tank etc..

Well the plants I got were from the pet shop so they should've been ok.

The substrate -I have heard that a lot of fish do like sand better and I have been planning to buy some but just needed to wait because I didn't have a job for about 2-3 months. Got one now so will get some shortly. It was donated this tank and the substrate came with it but I never really liked the look of red stones. I'm going to bunnings today and so I could get play sand. Is there anything I should look for on the packet to say that it's ok for fish? Wouldn't they sanitise the sand for kids??

Also I'm now actually worried I having been feeding the corydoras enough -I've been feeding them algae tablets (broken up) every second day

 

[Byron]

The substrate -I have heard that a lot of fish do like sand better and I have been planning to buy some but just needed to wait because I didn't have a job for about 2-3 months. Got one now so will get some shortly. It was donated this tank and the substrate came with it but I never really liked the look of red stones. I'm going to bunnings today and so I could get play sand. Is there anything I should look for on the packet to say that it's ok for fish? Wouldn't they sanitise the sand for kids??

Play sand is ideal substrate. I have it in all my tanks now. It is the most refined (to make it play safe) sand. Very inexpensive compared to so-called aquarium sands. I don't know what play sand you might have in Australia, but I cannot see it being a problem in any respect if it is just pure play sand.

To the other issue here...I will not guess as to the cory issue, as it could be one of several things. Diagnosing fish problems/disease is the most complicated thing about this hobby as there may often never be external signs. But I seriously doubt the new plants had anything to do with this.

As for feeding cories, they need sinking foods like pellets, tabs and disks. A variety is best, to ensure a complete nutrition. Algae-based disks are fine as one food, since they tend to have "fish" in them as well, and fish benefit from some "veggie" foods as it helps their digestive tract. I don't usually break them up, as other upper fish are more likely to grab them, and the cories like to bunch up around these disks and graze away. Shrimp pellets are an ideal food. For any of the sinking foods, brands do matter. Omega One and New Life Spectrum are two of the best; they have little or no "fillers" and actual fish meat. I also use Nutrafin's tabs which has earthworm in it, another cory favourite. Frozen bloodworms are fine but only as a treat, no more than once a week.

 

[Woody781]

Its worth checking out http://aqadvisor.com/AqAdvisor.php. According to that 4 corys is already overstocked without the tetra.

FWIW Corydoras should be on a sand substrate as their barbels are easily damaged and can get infection from rooting around in gravel. Mentioning that because when you are overstocked a single dead fish could be sufficient to cause the ammonia spike, even if it died of something else.

As Fluttermoth says: Try to move them ASAP. If possible put your old filter in there, alongside the new one as it will help with the cycle.

That website doesn't bring up my tank. How many cories should I have? 3-4 was recommended to me. They were informed about what size tank and how many tetras I had and someone said to me they are a low to mid tank fish (not sure if that's how you word it) and tetras were mid tank fish so that should be fine. I'm a novice -I rely on both the Internet and other people's advice

 

[Woody781]

Play sand is ideal substrate. I have it in all my tanks now. It is the most refined (to make it play safe) sand. Very inexpensive compared to so-called aquarium sands. I don't know what play sand you might have in Australia, but I cannot see it being a problem in any respect if it is just pure play sand.

To the other issue here...I will not guess as to the cory issue, as it could be one of several things. Diagnosing fish problems/disease is the most complicated thing about this hobby as there may often never be external signs. But I seriously doubt the new plants had anything to do with this.

As for feeding cories, they need sinking foods like pellets, tabs and disks. A variety is best, to ensure a complete nutrition. Algae-based disks are fine as one food, since they tend to have "fish" in them as well, and fish benefit from some "veggie" foods as it helps their digestive tract. I don't usually break them up, as other upper fish are more likely to grab them, and the cories like to bunch up around these disks and graze away. Shrimp pellets are an ideal food. For any of the sinking foods, brands do matter. Omega One and New Life Spectrum are two of the best; they have little or no "fillers" and actual fish meat. I also use Nutrafin's tabs which has earthworm in it, another cory favourite. Frozen bloodworms are fine but only as a treat, no more than once a week.

Hi Byron, so how often would you feed the cories? (there's only one now) Also I would like to get more cories but once the amonia is sorted out -how many would you suggest? I'll go by the fish shop when I go out today and pick up some different foods for my Cory. I'll pick up some sand too.

 

[Byron]

How many cories should I have? 3-4 was recommended to me. They were informed about what size tank and how many tetras I had and someone said to me they are a low to mid tank fish (not sure if that's how you word it) and tetras were mid tank fish so that should be fine. I'm a novice -I rely on both the Internet and other people's advice

Hi Byron, so how often would you feed the cories? (there's only one now) Also I would like to get more cories but once the amonia is sorted out -how many would you suggest? I'll go by the fish shop when I go out today and pick up some different foods for my Cory. I'll pick up some sand too.

Corydoras are shoaling fish, and a minimum of five should be considered; the "dwarf" species need more than this, but in the photos you have (had) Corydoras paleatus, the Peppered Cory, so five is minimum. More will always be better, but one has to keep the tank size in mind and you will be OK with five or six, but best to wait for that larger tank. And, we still are not sure of what was the issue here.

Once a day is sufficient for feeding. You can even miss a day or two...you should never feed prior to a water change as it can unsettle the fish trying to digest when there is commotion around them. To get only one addition food, I would suggest the Omega One shrimp pellets, a small can.

 

[Woody781]

Once a day is sufficient for feeding. You can even miss a day or two...you should never feed prior to a water change as it can unsettle the fish trying to digest when there is commotion around them. To get only one addition food, I would suggest the Omega One shrimp pellets, a small can.

Good to know about never feeding before a water change!! I always feed them after. I've had my cories for at least 4 months and only really feeding them algae wafers so maybe it was due to their diet?

So I went to the pet shop anf got persuaded into buying these sinking wafers but I got some blood worms too