Issues with new tank and cory catfish

Hi, I'm new to owning fish and I have had some problems with my tank. I have a 20 long with gravel topped with sand substrate, and ive planted java fern, amazon sword plant, crested java fern, moneywort, anubias, and a moss ball. I let the tank cycle for two weeks before getting any fish. I got 4 Julii cory catfish and one panda cory catfish, as well as a couple small shrimp. I let them settle in and I did not have any issues with them, I later got 2 ghost catfish and and one Colombian zebra pleco. I also have three fake rocks in my tank and a piece of driftwood. I first noticed some issues around a couple weeks after I got my fish, one of my julii cory was lethargic and seemed to have a bit red gills. I thought it might have been because of high ammonia however it was between 0-.25 ppm and none of the other fish appeared the same way. I did a water change and added api ammino lock just in case. later the week two other corys passed away, they seemed to have issues with their swim bladders since they were not able to swim straight. I picked up api melalax and api pimafix to take care of any possible issues. Throughout this my ph has been around 7.4-7.6, temp 76, and nitrates, nitrites and ammonia at 0 ppm. my other fish passed away a couple days a couple days after the corys. After this I had one Julii and panda left. they were all good for a couple weeks but this past week my Julii passed away and now my panda is looking sick. I also used microbe lyft to treat any parasites a couple of weeks before, since I noticed some small white worms on the glass. the worms did not appear to harm the fish and looked like detritus worms. I just don't know what is causing this it does not appear to be fin rot, itch or dropsy I think it might be a bacterial infection or possible constipation however I use the recommended food for my fish and fast them two times a week. they get fed specific wafers for cory, shrimp wafer, and algae wafer, and some frozen food. they get fed once a day and I make sure to clean out the excess food. my shrimp have been good this whole time and my water parameters have stayed constant besides a couple days of raised ammonia in the beginning of my tank set up. Any help or possible reasons as to why this is happening would be amazing I just feel horrible that they are passing away and it feels like I am unable to help them. I'm planning on treating with stronger antibacterial but besides that I'm not sure. Also when I do water changes I use api stress coat and api quick start and I do a 25 percent water change every two weeks. Thank you for any advice on what I should do.

You are dumping in too many "treatments." No matter what it is, each of these does cause stress to fish, so they should never be used unless you are as certain as you can be that you know the actual problem, and then only if the medication is the best and safest for that specific problem. A major water change is usually more effective. And any antibiotic is never safe except under these conditions.

Can you post a photo of the tank? We might spot something. I have some ideas, but won't throw them out unless I see evidence.

And, how did you cycle the tank?

Thanks so much for replying, I definitely felt that way but I was told it was safer to use the water treatments then do major water changes. And my panda cory is not looking very good he mainly doesn't move to much and has difficulty with his balance, but he can still swim a bit and is eating still. My tank water is a bit discolored since I have the drift wood in there and it was not pre soaked. I also did a 25% water change a couple days ago.

Looking at your aquarium and reading tween the lines, sadly you're advice from the store is entirely wrong and this is going to end in tears...lots of them

Two weeks is nowhere close to enough time for a cycle. Without livestock you are looking at 7-9 weeks, with livestock you are looking at 9-12 weeks.

Shrimp should not be placed in an aquarium that has been running and fully cycled until at least 6-8 months, they don't tolerate new aquariums.

As @Byron absolutely correctly said, you have way too much "stuff" going in there......AmmoLock will kill a cycle in a newly set up aquarium so using that you have stopped the cycle before it got going - the good bacteria needed to keep ammonia, nitrite etc out of the water have been starved to death by using ammonia killing chemicals

I am not going to sugar coat things as this mess is not your fault since the advice given at the shop was as so often the case an exercise in making a sale rather than being useful to you

Give the information on this link a really thorough read...


I would strongly suggest that you return all livestock to wherever you bought them and take the additive supply too...you have spent alot of money for absolutely no reason and you are not the first to be sold all manner of stuff under false pretences.

All you need is a dechlorinator, a filter kickstarter and alot of patience. Read the link provided, study it carefully and ask if stuck. The store has done you absolutely no favours and the hard work starts now.

The plants should help you, I assume they are growing. After two weeks there is no indication of failing (dying plants) that I can see, so this is one positive.

Do you know the GH (general hardness) of the tap water? Check the website of your water authority, it may be given there. The pH we have in the mid-7's.

It is quite possible the fish became erratic and died due to all the chemicals. When fish cannot properly swim, everyone starts calling it "swim bladder" problem, but it is very rarely any issue with the swim bladder. Several things can impact the fish's ability to function properly, from water parameters (or sudden shifts in pH), to high ammonia, nitrite or nitrate, to an internal protozoan, to some genetic disorder...most of us do not have anywhere near the capability to recognize all of these. Water changes increased are always a good thing for such problems, whatever the source. I would do some major water changes, meaning 70% of the tank volume, each day. Provided the GH, pH and temperature of tap water and tank water is basically the same, this cannot do any harm, and may benefit.

Do not acquire any new fish until you/we have this resolved. There are issues with the number and species, we can go into that later.

Is the gravel just inert gravel, or is it some sort of plant substrate material? And is the sand regular inert aquarium sand?

Byron said:

The plants should help you, I assume they are growing. After two weeks there is no indication of failing (dying plants) that I can see, so this is one positive.

Do you know the GH (general hardness) of the tap water? Check the website of your water authority, it may be given there. The pH we have in the mid-7's.

It is quite possible the fish became erratic and died due to all the chemicals. When fish cannot properly swim, everyone starts calling it "swim bladder" problem, but it is very rarely any issue with the swim bladder. Several things can impact the fish's ability to function properly, from water parameters (or sudden shifts in pH), to high ammonia, nitrite or nitrate, to an internal protozoan, to some genetic disorder...most of us do not have anywhere near the capability to recognize all of these. Water changes increased are always a good thing for such problems, whatever the source. I would do some major water changes, meaning 70% of the tank volume, each day. Provided the GH, pH and temperature of tap water and tank water is basically the same, this cannot do any harm, and may benefit.

Do not acquire any new fish until you/we have this resolved. There are issues with the number and species, we can go into that later.

Is the gravel just inert gravel, or is it some sort of plant substrate material? And is the sand regular inert aquarium sand

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I have had my tank for a little over two months, and I used regular aquarium sand and gravel. I also use flourish to supply CO2 to the plants. unfortunately my panda Cory did not make, I still have my shrimps but Im not sure if I can return them since its been a couple months. And my water parameters have stayed constant throughout my fish passing, the ph tends to be a bit basic around 7.4, I do have a some driftwood to help a bit. My plants have been doing very well none of them have died and they are growing well. Thank you so much for all your help I really appreciate it. I also make sure to add API quick start when I do my water changes to help add beneficial bacteria.

Jordank said:

I have had my tank for a little over two months, and I used regular aquarium sand and gravel. I also use flourish to supply CO2 to the plants. unfortunately my panda Cory did not make, I still have my shrimps but Im not sure if I can return them since its been a couple months. And my water parameters have stayed constant throughout my fish passing, the ph tends to be a bit basic around 7.4, I do have a some driftwood to help a bit. My plants have been doing very well none of them have died and they are growing well. Thank you so much for all your help I really appreciate it. I also make sure to add API quick start when I do my water changes to help add beneficial bacteria.

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Once again, there are too many substances entering the water, as they get inside fish. Flourish Excel should never be added to a tank with fish (there will be arguments over this, I don't care). the API is less harmful but not necessary. A basic good water conditioner is all you need, with maybe a plant comprehensive supplement. I have to go off for my cancer treatment now, but may have more to explain when I get back if needed.

Thank you for all your help, do you have any ideas what may have caused my fish to pass, is it because I used to many treatments? Also is there anything I can do to help fix this, should I do a large water change or just start a new tank? Thanks

Jordank said:

Thank you for all your help, do you have any ideas what may have caused my fish to pass, is it because I used to many treatments? Also is there anything I can do to help fix this, should I do a large water change or just start a new tank? Thanks

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Water changes. No need to start a new tank and need to start your cycling all over again

Agree, water changes. You have not given us the GH of your tap water (pH is 7.4 as mentioned).

I cannot say the various substances in the water caused this, any more than I can say it was some protozoan or other health issue, or just genetics. But all the additives do have problems weakening fish and adding stress, and that is not helpful especially if they are dealing with some other issue like a health one.

Would you recommend doing a 50% water change? And i don't have a reliable test for GH yet, I will pick one up I just have the freshwater api test kit and some 6 in 1 strip tests but they're not to reliable. From the strip test the GH appears to be around 150 ppm

Jordank said:

Would you recommend doing a 50% water change? And i don't have a reliable test for GH yet, I will pick one up I just have the freshwater api test kit and some 6 in 1 strip tests but they're not to reliable. From the strip test the GH appears to be around 150 ppm

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Provided the parameters--and this refers to the GH, pH and temperature--of tap water and tank water are reasonably the same, the more water you change the better, always, and especially when dealing with "something." A change of 70% would be my first action, and another tomorrow wouldn't hurt. You want to remove as much of the tank water as you can, to remove the substances.

The strip GH test is good enough. This is 180ppm [= 10 dH] which is a tad on the hard side for cories but not so much as to cause the issues.

Thanks so much, and would the api stress coat water conditioner be ok, or should I use a different one? I have both the seachem prime and tetra water conditioner

Given the options, I suppose the Prime is your best bet. But it is not a conditioner I would ever use or recommend except in situations where ammonia, nitrite and nitrate may be issues. The Stress Coat has aloe vera which does impact fish gills. The Tetra AquaSafe says it has plant extract without saying just what it is, so that's a warning bell. While none of these is likely to kill the fish, unless overdosed, they still cause issues that weaken them. The API Tap Water Conditioner is about the safest and most effective conditioner there is.