What do I do next time?

[GaryE]

I know, but I'm afraid there might be a parasite or something still living in the tank. I know stuff you've mentioned now, I'm just wondering if there's anything else to prevent early cory death.

No. There is no medicine, for humans or fish, that takes care of everything before it develops. If you stop, you realize what you're asking, and it's for something that would be on everyone's wishlist.

So you maintain the tank properly, do your water changes, feed well (but don't overfeed) and more importantly, have a bit of luck this time with your purchasing. If you start with healthy Corys, you'll have them for at least ten years. To achieve that, the water will be clean, the cycle respected, the tank will be large enough... and you will be the med you want to buy. It's a tiny bit of work that will do it - not anything you can buy.

 

[VioletThePurple]

You say here ammonia was zero, but in your post about the cories you said you only had test strips (known for being inaccurate) and they don't test for ammonia - so which is it? You also cleaned out the filter with tap water when you first noticed issues, so it's quite possible you ended up with spikes due to killing off some of the beneficial bacteria which made problems worse for the fish. You also said you went a week without testing water, so again you probably missed some ammonia, nitrite & nitrate spikes. Your gravel substrate wasn't good for cories and causing them stress which weakens their immunity. Prior to you noticing the major issues, you were only changing about 25% water every 2 weeks, which may not have been nearly enough, but you wouldn't know as weren't testing daily and weren't testing ammonia at all. You had to separate your betta due to aggression, it possibly was also harassing the cories, but you just didn't see it. You also said in one of your earlier posts that you didn't have a siphon so never cleaned the gravel - a very real issue for bottom-dwelling fish like cories.

So yes - it is highly likely tank conditions were the major factor contributing to the issues you've had. And remembering that by the time you noticed the issues and started doing something about it, the fish had likely been slowly degrading for some time in those less-than-ideal tank conditions.

I got an ammonia test recently before they all died, and it showed up as 0. Plus, when I first noticed something was wrong, I started doing partial water changes daily. I did clean when I got a siphon, before I was only doing a little bit with a turkey baster, I agree with you on that, it probably was an issue, but even after siphoning they still died off. When I moved a cory to quarantine (starting with some old tank water, new water same temp, no substrate, it still died so how could substrate or water quality have been an issue in that scenario?

Even if test strips are inaccurate, (what else was I supposed to do- the stores are sold out of freshwater test kits) I was doing daily partial water changes which would have helped out with water quality. I was told by another user that cleaning the filter with tap water it wouldn't hurt BB since the tank is established. But I agree, that was a mistake and next time I only cleaned with tank water. Wdym every two weeks might not have been enough? Every website I read says to change 25% every two weeks. I doubt the betta harassed the cories, I think that problem only came up because I was testing the betta's limits by adding fish that occupy the same area in the tank.

I still highly doubt it is tank conditions, but once I'm able to get a complete test kit I'll know for sure. I admit, it was probably from the lack of proper gravel cleaning. I have slowly replaced the gravel with sand (not completely all at once because I don't want to risk losing BB like I did with the filter.) And now I have a siphon which I will clean the gravel with during water changes. (Since the siphon takes out water anyway.)

I'm just frustrated because people keep telling me about the same advice over and over, (most of which I've already applied or am applying now) that I follow that couldn't save a cory.

 

[VioletThePurple]

That's exact it.
"Daily partial water changes at first signs of sickness" isn't what we all are talking about.

Good husbandry and balance prevent sickness and will not cure fish afterwards (fin rot maybe).

Also, meds don't prevent getting ill but only are usable as last resort when they do get ill.

Patience, clean water, enough space, good tankmates, good food, peaceful tankmates, etc. etc... are the cheapest way to prevent fish getting sick.

Even when meds are use one should ask himself / herself how the fish got sick.
Meds don't remove most causes (only introduced parasites maybe).

Meds aren't the solution and especially not as they are "general".

I'm asking for med recommendations in case this happens again with future cories I get. So, by your advice I shouldn't change anything because I now have most of the proper maintenance supplies. So, what I'm getting from you is that water changes for sick fish don't do anything. I guess the "When in doubt, do a water change." saying is wrong by your logic.

 

[VioletThePurple]

You really shouldn't argue, when you are clearly wrong. You had gravel, which accumulates large pockets of anaerobic bacteria, and the corydoras are oversensitive to targeted spikes of ammonia, which happen near the substrate, and they suffer for a long time before showing symptoms, once they do, in the manner you had, it is too late to fix it.
If you water parameters were "fine" across the whole tank, not the surface area where you took the sample from, the fish wouldn't be dying, now would it? Even if it were a disease, it only matured and spread because the tank conditions allowed it.

But sure, "couldn't have been" water condition, with this approach, you will face the same situation again, since you clearly don't want to listen to advice given...

I just don't understand how it could be water conditions when all the tests came up fine. And I was doing daily partial water changes so if that was an issue that should have taken care of it. You're right about the too late part. I'm replacing the gravel with sand and will buy a test kit when it's back in stock.

 

[Oblio]

Good price here on API Master Test Kit if you haven't found one already

https://www.amazon.com/dp/B000255NCI/?tag=ff0d01-20

 

[Byron]

"Good husbandry" has many facets. Regular water changes (once weekly going forward) of a useful volume--the more the better, but 25% biweekly is frankly less than useful. If the parameters, meaning GH, pH and temperature, between the tap water and tank water are reasonably the same, you should change 50-70% once a week. You can read why in my article at the head of this section (Tropical Discussion) of the forum.

Do not rely on advice online unless you know the source is reliable. Same holds for fish store staff. And, unfortunately, the claims of many manufacturers have to be taken with the proverbial grain of salt.

All "water conditions" cannot be measured, there are no tests for pathogens or things like pheromones and allomones--this is why we do largish water changes. Did/do you dig into the open areas of the substrate during these water changes? This is one possible issue. The photos of the dead cories in whichever thread clearly indicate bacterial (could also be roughness but I think most agreed it was bacterial) erosion of the barbels. Sand will help this problem, along with water changes. And at the first sign of trouble a major water change is advisable (with parameters OK).

Ammonia and nitrite may now be zero, but if either was high initially it can permanently affect some fish. I'm not saying this happened here, just pointing out it can happen. Dying fish weeks and months later can sometimes be traced back to this, or some other issue, which the fish live through but not without repercussions.

Medications should never be used unless one is fairly certain the medicine is really needed and it is safe for the fish and it is the best under these criteria to treat whatever problem it is. Most medications will cause some detriment to fish, so you do not want to be using them unless absolutely necessary. Substances that dissolve in the water are likely to enter the fish with the water that is continually passing through the cells and into the bloodstream. This obviously has some impact on the physiology, so avoid them unless necessary. Diagnosing fish disease is not at all easy; I have been keeping fish over 30 years and I only recognize a couple of things. There is also the problem of acquiring "sick" fish. And there is no preventative or cure-all medication, regardless of what manufacturers may claim.

 

[DoubleDutch]

I'm asking for med recommendations in case this happens again with future cories I get. So, by your advice I shouldn't change anything because I now have most of the proper maintenance supplies. So, what I'm getting from you is that water changes for sick fish don't do anything. I guess the "When in doubt, do a water change." saying is wrong by your logic.

Yep. Waterchanges are part of the prevention / precaution AND a good idea in case of possible poisoning, lack of oxygin etc....
Waterchanges indeed do nothing for or against illnesses popping up.

 

[VioletThePurple]

"Good husbandry" has many facets. Regular water changes (once weekly going forward) of a useful volume--the more the better, but 25% biweekly is frankly less than useful. If the parameters, meaning GH, pH and temperature, between the tap water and tank water are reasonably the same, you should change 50-70% once a week. You can read why in my article at the head of this section (Tropical Discussion) of the forum.

Do not rely on advice online unless you know the source is reliable. Same holds for fish store staff. And, unfortunately, the claims of many manufacturers have to be taken with the proverbial grain of salt.

All "water conditions" cannot be measured, there are no tests for pathogens or things like pheromones and allomones--this is why we do largish water changes. Did/do you dig into the open areas of the substrate during these water changes? This is one possible issue. The photos of the dead cories in whichever thread clearly indicate bacterial (could also be roughness but I think most agreed it was bacterial) erosion of the barbels. Sand will help this problem, along with water changes. And at the first sign of trouble a major water change is advisable (with parameters OK).

Ammonia and nitrite may now be zero, but if either was high initially it can permanently affect some fish. I'm not saying this happened here, just pointing out it can happen. Dying fish weeks and months later can sometimes be traced back to this, or some other issue, which the fish live through but not without repercussions.

Medications should never be used unless one is fairly certain the medicine is really needed, and it is safe for the fish, and it is the best under these criteria to treat whatever problem it is. Most medications will cause some detriment to fish, so you do not want to be using them unless absolutely necessary. Substances that dissolve in the water are likely to enter the fish with the water that is continually passing through the cells and into the bloodstream. This obviously has some impact on the physiology, so avoid them unless necessary. Diagnosing fish disease is not at all easy; I have been keeping fish over 30 years and I only recognize a couple of things. There is also the problem of acquiring "sick" fish. And there is no preventative or cure-all medication, regardless of what manufacturers may claim.

In the article, you stated planted tank substrate should be mostly untouched. I have live plants. Should I not have cleaned the substrate?

 

[Byron]

In the article, you stated planted tank substrate should be mostly untouched. I have live plants. Should I not have cleaned the substrate?

When the biological system is functioning normally, digging into the substrate may not or should not (depending) be necessary. I never touched the sand in my cory tank. In the issue here, there clearly was a problem likely bacterial in nature, and that might have been helped by digging into the open areas. The gravel contributed to the problem, and the cories were not able to sift through it.