Please help my Corys keep dieing

[silvercory]

I am very distressed. My Cory keep dieing and I don’t know what to do. Please can you help.
I would like to think I am a reasonably competent fish keeper. I have kept fish off and on most of my life. Gold fish when I was very young. Then when I was in my teens I had cold water and also tropical fish for about years five years. Then recently about 10 months ago I started again. I had kept a few Cory’s before and feel in love with them. I find there behaviour so interesting they seam to have such personalities. So I decide to have a species only tank, having said theis I do have 5 ember tetra. I set up a 24 inch tank I have bog wood, Java Fern, Java moss. For Filtration an Ehiem 65 Aqua ball filter with an upgrade kit nearly doubling the capacity of the filter. I had slowly stocked my tank and have 15 Corys . I do a 50 Percent water change once a week and also make sure I hover the gravel every week as well. All was well in my tank I have had the odd couple of fish die since setting up the tank nothing major. The fish that had died where very thin when I got them and I suspect internal bacterial problems.
But in the space of about 3 weeks I have had three fish die, and two more are looking ill. Despite my efforts corys seam almost impossible to cure wants they start to get ill. The fish that have died in the last three weeks all follow the same sort of pattern. First they cant seam to swim off the bottom of the tank and they drag them selves around, then they become very buoyant and they start floating off the bottom despite the fish trying to stay on the bottom, then they lie on there sides breathing slowly finding movement almost impossible with there fins locked out, then they die. This all take place over a period of anything between 2 - 7 days from start of illness to death. The fish appear healthy and at the start they are keen to eat but as there condition progresses they lose interest in food. The fish show no obvious signs of diseases on there body apart from looking a bit pale. I am desperate to stop what seams to be a chain reaction of death. I have tried treating the fish with Interpet swim bladder medication, general tonic, anti Internal bacterial, also esha 2000. Not at the same time I must point out and only following the instructions. I don’t know what’s happening to my fish. There seams to be very little information available about Cory health. I have several Corydoras books and they offer no explanation. I am hoping someone will recognise the symptoms and offer some advice for treatment.

[silvercory]

Sorry forgot to include water details. They are as follows: Tested using Tetra Test Strips
Temp 22c cl2=0, ph=8, kh=6, gh=16, no2=0, n03=25. Gavel base in tank.

[Taratron]

NO2 being nitrite, I think your tank is in a cycle. What is the ammonia reading?

Do you gravel-vac the gravel, or just 'hover,' ie, hold the tube over the gravel rather than in it?

Where are you getting the cories from? Do you QT?

[Richard B]

One thing to seriously consider for long-term benefit to Corys is the substrate.

They can be kept in tanks with gravel but really, sand is the only thing that should be used. In the wild corys are found in areas with sand or silt beds, not gravel. When you talk to people who are recognised as leading the way/experts with corys, they all say the same - people like Ian, Hans-Georg Evers, Kim M etc etc. Only a fine layer of round grain sand is needed.

Pool filter or childs play sand often is a cheap source of suitable sand

[MatsP]

What species of Corydoras are they?

--
Mats

[silvercory]

I use a gravel vac which I push it down to the bottom of the tank wait for the debris to clear then move on to the next spot. I vac all the open areas of the tank once a week with the water change. Then once a month I lift up all the pices of bog wood and clean under them all. My plants are attached to bog wood to facilitate easy cleaning.
I am not sure what I think about the argument of gravel being not suitable I have read around the subject a lot and there seams to be lots of contrasting information. I personal think it depends on the species I can only document my personal experience. When I set up my main tank I used regular pea gravel this seamed to be ok but after a while but then I noticed some barbel erosion. I then switched to a different gravel: Pettex Gravel colour Highland. This is about twice the cost of normal gravel but I have experienced no barbel erosion on this gravel. I general don’t like sand I think its messy, it gets in the filter etc. I have several Corydoras tanks and in one of my smaller tanks I have experienced problems with Corydoras Trilineatus barbel erosion. The tank had a gravel substrate so I switched to silica sand the trilineatus are fine and happy no further problems with barbel. Before purchasing Conclour Cory’s I read that they are very sensitive so they are on sand with the Trilineatus. I also think sand is very beneficial for baby fish I have some very young Pandas on sand because of there small size I felt that sand was more manageable for the little barbles. I do love to watch them sift through the sand. So I am still undecided about the hole gravel sand argument as I say from my experience it seams to depends on the species.
The fish that have died where all from different fish shops I quarantine them for a couple of weeks. Before putting them in to main tanks.
The corys that had died where Aeneus x3 , Sodalis x1, Arcuatus x1. I have loss no more fish for over a week hopefully things are a bit more stable.

[dw1305]

Hi all,
These sorts of "unexplained deaths" are very frequently water quality related. You can't really measure water quality with test strips etc, they don't give you anything like an accurate enough reading. Even if you have lab. quality apparatus for measuring pH, O2 etc. you can't really quantify water quality, you need to use a parameter called "total BOD" (Biochemical Oxygen Demand). The measurement of total BOD can be very time consuming, so even most water testing labs. use the cut down "5 day BOD" procedure, but this isn't something that a hobbiest can do at home. http://en.wikipedia.org/wiki/Biochemical_oxygen_demand

Is your tank planted? the relatively high NO3 levels would suggest either that you don't have plants? or that your water change water is high in nitrates? Either way growing plants are probably the single factor that has the greatest effect on maintaining water quality. I'd strongly recommend plants to everybody for their beneficial effects on water quality.

I am not sure what I think about the argument of gravel being not suitable I have read around the subject a lot and there seams to be lots of contrasting information. I personal think it depends on the species I can only document my personal experience. When I set up my main tank I used regular pea gravel this seamed to be ok but after a while but then I noticed some barbel erosion. I then switched to a different gravel: Pettex Gravel colour Highland.

There are 3 main arguments for sand:
Sand or silt are the natural substrate that most Cories occur over, and a fine grained substrate allows them to display their natural feeding behaviour and reduces stress.
The second argument again relates to water quality, it is is likely that barbel erosion is at least partially related to water quality, rather than to abrasion by the substrate. Sand substrates have the advantage that any mulm, uneaten food etc sits on top of the substrate, rather than falling down the gaps between the gravel and compromising water quality. I've never had any problems with my relatively thick sand substrates ("pool filter" or the much finer "play sand") becoming anoxic, possibly because I have plants and MTS in all of my tanks. If you are worried about your sand going "bad", you can have a thin layer of sand (1 - 1.5 cm thick). I don't have any problem with sand going into the external filter in-take, as I try to disturb the substrate as little as possible. In fact I try to keep all disturbance (syphoning etc.) to a pretty low level. I also always have the filter intake covered with a coarse sponge. I want just the ammonia that the fish produce, that hasn't been mopped up by the plants, entering biological filtration (in the filter). A coarse sponge on the filter intake doesn't reduce water flow very much, takes care of mechanical filtration and is quick and easy to clean regularly.

The final reason is probably the most important, the Cory experts on this forum recommend sand, and I'm pretty sure that they know a lot more about Cory keeping than I do. If Ian Fuller says "sand", sand it is.

cheers Darrel

[Richard B]

The final reason is probably the most important, the Cory experts on this forum recommend sand, and I'm pretty sure that they know a lot more about Cory keeping than I do. If Ian Fuller says "sand", sand it is.

cheers Darrel

Absolutely agree - and hearing Hans-georg Evers speak aabout Corys it is the one thing he practically begs people to ensure they do

[silvercory]

Hi I am new to this forum, just wanted to say thank you for people taking the time to write responses. Some one else has also has just mentioned to me also that my tap water my be high in nitrates when it comes out of the tap. I have currently used up all my Tetra test strips and shall have to purchase some thing a bit more detailed and scientific. I wonder if they are any test kit sets that anyone could recommend? If my tap water is high in nitrates is there any thing I can do?
My tank is planted I have the following two Anubias barteri var. nana 'Petite', one clump of Java moss, and four very large clumps of Java Fern. You have raised some interesting points about sand. Please can you tell me what MTS stands for? You mention silt for use in tanks what exactly is it? I tend to think that silt is just small granules of all kinds of things; soil rock, sand etc. Is it some thing you can buy?. Your point about debris being trapped gravel effecting the water quality and the water quality then effecting the barbels makes sense. I have seen fish for sale with worn down barbels despite being on gravel.

[AndiH]

For test kit, I use API; I don't know the equivalent in UK. MTS stands for Malaysian Trumpet Snail. They like to burrow through sand and keep it loose and without pockets anaerobic bacteria can grow in.

[Vlacek]

First time I've bought panda cories, they all looked ok in shop but were in bad condition (especially barbels) when I brought them home some hours later. And this was only caused by stress. I've lost one fish and it took more than month for the others to fully recover. Even worse with duplicareus - I have six, had to replace gravel with sand (redesign whole tank) so put them into smaller tank for couple of hours. They were so stressed that they almost lost all black color on the back (even though I kept them in darkness). Four of them fully recovered but two of them never got their black and orange color back (although doing fine otherwise). So stress plays a role as well. I think they can be quite stressed every time you vac and move wood etc. in the tank.
Also one positive thing I've experienced when I replaced gravel with fine sand - I almost don't have to vac the ground! This is because cories dig in the sand and all debris is raised by their movements and ends up in filter. Simply great! It's easier to clean the filter (I have inner one) than to vac all around. This also means less stress for fish.

Martin

[dw1305]

Hi all,

Some one else has also has just mentioned to me also that my tap water my be high in nitrates when it comes out of the tap. I have currently used up all my Tetra test strips and shall have to purchase some thing a bit more detailed and scientific. I wonder if they are any test kit sets that anyone could recommend? If my tap water is high in nitrates is there any thing I can do?

Try contacting your water company for a nitrate reading, nitrate levels would almost certainly be high (they are all over the arable areas of the E. of England), but I know Anglian Water has had to put in water treatment plants in some areas to keep below the 50ppm NO3 limit. <http://www.acwa.co.uk/anglian_water.html>. The nitrate test strips will work on your tap water, and give you a ball park figure.

The only realistic options for nitrate reduction are RO water, nitrate ion exchange resins or bio-filtration with plants. The plant option works pretty well and is a lot, lot cheaper than the first 2. The plants you have are all pretty slow growing, what you really want are some fast growing plants that have access to aerial CO2, this makes them both easy to harvest and removes CO2 as a limiting factor for growth.
Limnobium (Amazon Frog-bit), Pistia (Water Lettuce), Salvinia (Floating Fern) or Lemna minor (common Duckweed) are all excellent (and Duckweed is free), but Limnobium or Salvinia are easiest to manage. PM me if you can't find them and I'll post some.

You mention silt for use in tanks what exactly is it? I tend to think that silt is just small granules of all kinds of things; soil rock, sand etc.

Yes silt is just very fine sand, we don't tend to use it as substrate because it clouds the water, this makes it difficult to handle. Sand is fine. I tend to mix some clays (usually calcined, but sometimes raw) and humus in with my sand to increase the CEC of the substrate, but this isn't essential. If you do have a substrate you can plant Echinodorus (Amazon Swords) and Cryptocorynes these will also convert NO3 into leaf material, bit it is more difficult to export from the tank (the floater can just be skimmed of the top).

cheers Darrel

[corywink]

An alternative to sand is very fine gravel, grain sizes around 1mm. This is what I use in my cory tanks, and I've experienced no barbel loss, the corys can dig in it and it's heavier than sand so not as messy.

[Garfed]

Do you have gravel-vac the gravel, or simply "stable", is to keep the tube in the sand instead of there? Where are you Coria? Is QT?

[Anthonyck]

Having an interest in Corydoras Aeneus just about forever, I had read this post prior to buying a pair (I know I should have gotten more, but wanted to see how they did before committing to more...). They were a very young pair and were doing quite well in my tank with ghost shrimp, goldfish, and a Chaetostoma Malesi (Bulldog Pleco). Within a couple days after adding them, I got hit with ich and treated with a natural remedy and was already using salts. The goldfish and corydoras never were symptomatic, and while the pleco was lost (sniff), another fish (silver molly) was seemingly cured by the treatment, which I was instructed to continue. It should be said that I just returned from a 10-day vacation, during which the pleco died. Of course, I had an experienced fish owner providing the medication daily and feeding.

I did a 50% water change upon returning, the pleco already having been removed. The corydoras were doing great and had no signs of ich. I added some slate "hiding spots" similar to something I had seen on this site and also both java fern and java moss, as well as four more shrimp, since they seemed to be doing fine with the "shrimp-safe" ich treatment and also not suffering any problems themselves (I have yet to lose one in this tank). Interestingly, within hours, they (the albino cory cats) started exhibiting similar behaviors, and I fear, might not last the week. One is worse than the other, but I think both will be lost.

This tank, it should be noted, is my 29gal tall tank. It's 72-74F, 7.2-7.5 pH, with the wrong type of gravel (sorry, action before research, shame on me) and live plants(hornwort, bacopa, and the two new additions - mentioned above). The tank is still only a couple months old.

I know the water A) Finished the nitrite portion of its cycle, as it tested a little high before I left and perfect just yesterday, before the water change, and B) Must have hit a nitrate stage, as my hornwort grew 6 inches in a 10 days while I was gone. I would hypothesize that one of, or some combination of the: java fern, java moss, or invasive manipulation of tank furniture (like gravel siphoning, which I never do in this tank), led to the problem. This was only the second water change since I added these guys and first "redecorating" done, to be sure.

Does anyone think there is some data to be reaped here? I want to get more albinos, and maybe a few pandas, before I add some petricolae to this tank. I for certain need to know my tank is safe before I waste money and risk killing fish. Help!

[Anthonyck]

I am happy to report that my two tiny Aeneus seem to be on the mend. Not knowing any better, it really seemed like the stress of the heavy-handed manipulation of tank contents spooked these guys. If they continue to improve, I will follow through with the plan to add 2-3 more of the same species in this tank.

[Anthonyck]

....once it appeared that they were doing well, I added 3 new tank mates of the same species. Immediately the group perked up and seemed to be frolicking nicely. After a da or two, however, the one of the original two who had been worse off before, stated doing the same things and worse. At point, it was near the bottom and trying to swim to the food, only accomplishing a spiral type of path, as if one side of fins were paralyzed. I thin this fish may have a problem when I got it, bit I suppose there is no way of knowing. It died in the last couple days. Interesting part of having shrimp in the tank - dead bodies aren't as obvious, and far less messy to remove.