Corydoras unknown death

[Bicyclemaster]

Hey everybody,

I recently stocked my 10g tank and after about 3 days one of my cories died. As a side note, this is my first aquarium.

So, I let the tank cycle for about 3-4 weeks, it is mildly planted with enough hiding spots. As for the fish, I put together a female betta, a neritina snail and 2 panda cories. I did this because i wanted to see if the betta is an agressive type and since i don't have the money for a quarantine tank(so yea, i cannot quarantine them), i thought i'd rather have 2 dead fish then multiple. If she was non-agressive i was going to get 2-3 more cories.

I have a boyu wf 2015 filter and the heater is called "aquazonic eco aquarium heater". They ar pretty much no names.

I only added dechlorinator to the water. Since it has only been 3 days i didn't had the chance to do a water change. As for food, i was feeding the betta about 2-3 betta granules 2 times a day and half of the sinking wafers from Tetra for the cories once a day.

My nitrates and nitrites are are preatty much close to 0 since they were recently added and the ph is 7.5. I cannot test ammonia with the strips i have.

Two more things: the betta is quite gentle, she only nipped them about 3 times at the beginning and then she stopped. She would sometimes find them, look at them, then leave. The other thing is, i noticed my temperature over the night went down from the normal 25 Celsius to 22-23. I'm probably going to change the heater.

I believe he was heavily stressed from only being 2 of them in the aquarium but i would gladly appreciate your help.
I remembered something else. The cory was rapidly breathing all the time and both of them seem scared to go scavenging. Also i believe the cory was a bit redish after death, but he might have been dead for a few hours since i found him in the morning

 

[jonny-5]

I would be checking Ammonia levels. Red or inflammed gills in any fish is a good sign that Ammonia is present. The gasping could also indicate lack of oxygen but more than likely the gills indicate something else.
3-4 weeks does not seem long enough to cycle a tank but i dont know enough about your cycle process. As you said Corys do much better in a nice sized group but a 10 Gallon will be to small for that. Water changes will help here, Every day if needed. Beneficial bacteria does not live in the water column, It lives everywhere else but that. Hope this helps a little. By the way im no expert but i have kept Corys for 20 years

 

[Bicyclemaster]

I would be checking Ammonia levels. Red or inflammed gills in any fish is a good sign that Ammonia is present. The gasping could also indicate lack of oxygen but more than likely the gills indicate something else.
3-4 weeks does not seem long enough to cycle a tank but i dont know enough about your cycle process. As you said Corys do much better in a nice sized group but a 10 Gallon will be to small for that. Water changes will help here, Every day if needed. Beneficial bacteria does not live in the water column, It lives everywhere else but that. Hope this helps a little. By the way im no expert but i have kept Corys for 20 years

Thank you so much for the feedback. I cycled the tank by using some plants from an acquaintance so I think it should be cycled by now but you never know. The other cory looks fine, no red on him or anything, but of course i'm going to check ammonia. Do you think it's okay if i add a few more corys so the lonely one doesn't get to stressed? I'm going to check ammonia before this and start doing daily 10% water changes.

 

[jonny-5]

I would not add anything else to the tank until you manage to find the cause. Hopefully it will be some ammonia spike that will dissapear with daily water changes.
For me the plants from a friend possibly wont harbour enough bacteria for a full cycle in 3-4 weeks. I would leave what you have right now & change the water 10% daily then keep checking all the stats of the tank. I would also recommend a liquid test kit as the dip tests are not great for accuracy.
Im not saying your doing anything wrong, Just trying to give a bit of what i have done in the past.
Hopefully this will help

 

[Essjay]

If you have only a couple of plants, there won't be enough for a plant cycle - this is where a lot of fast growing plants are put in the tank, and once they start to grow they remove the ammonia excreted by the fish.

With just a few plants, they won't be enough to remove all the ammonia. The bacteria on the plants won't be enough either, they have to grow more of them and that means feeding them with ammonia.

As jonny-5 says, you likely have ammonia in the water due to the tank not being cycled, and with insufficient plants. This will be probably followed by nitrite.
You need a test kit which tests for ammonia and nitrite - liquid testers are better than strips. Then test every day and if either read more than zero do a water change big enough to get them to zero. Once the levels stay at zero for several days, the tank is cycled for the fish currently in the tank. More fish must be added a few a time to allow the bacteria to catch up.

Floating plants will help a lot. They are very good at taking up ammonia, and they give the fish a 'roof' so they feel safer.

 

[DoubleDutch]

Thank you so much for the feedback. I cycled the tank by using some plants from an acquaintance so I think it should be cycled by now but you never know. The other cory looks fine, no red on him or anything, but of course i'm going to check ammonia. Do you think it's okay if i add a few more corys so the lonely one doesn't get to stressed? I'm going to check ammonia before this and start doing daily 10% water changes.

Wait with more Corys till your tank is properly cycled. 10% won't be enough.

Corys are quite sensitive to nitrogyn compounds

 

[Bicyclemaster]

Thank you everybody for the replies.

I looked a bit more into it and i realise i have to do a fish-in cycling. This friend of mine who has been wlrking in the fish industry for 20 years told me that i could cycle the aquarium with only the plants and it would also be faster. Sadly i did the mistake of listening to him. I am going to buy some tests today and depending on what they read i will try to do water changes so that the ammonia levels stay around 0.25 in order for bacteria to start appearing. The nitrite seems to be at 1 at the moment so i believe there are some niteosomonas in the tank.

I have one last question: once i am done with the cycle i want to add corys again so, how many at a time can i add as to not create an ammonia or nitrite spike?

 

[Slaphppy7]

First things first...get the tank cycled with the fish you have now, then you can consider more fish in the future

See the fish-in cycling sticky here: https://www.fishforums.net/threads/cycle-your-tank-a-complete-guide-for-beginners.475055/

Get one of these ASAP, you will be testing water daily: https://apifishcare.com/product/freshwater-master-test-kit

You need a good quality water conditioner, again ASAP, get either some Seachem Prime, or API Tap Water conditioner

Read the cycling sticky, and post any questions you may have about it here

 

[Bicyclemaster]

Sadly i don't have the money to buy an API test kit and they're also not sold where i live. What i can buy is this:

sera ammonium/ammonia-Test (NH4/NH3) | sera

sera NH4/NH3-Test - Water test for aquariums ✔ checks aquarium water for ammonium and ammonia ✔ optimize water parameters ✔ Find out more now!

www.sera.de

Or this:

JBL NH4 Ammonium Test

Checks the biological balance (bacterial activity) in freshwater and marine water

www.jbl.de

I am reading the sticky right now and i will see what conditioner i can find at my local pet store.

 

[Slaphppy7]

Sadly i don't have the money to buy an API test kit and they're also not sold where i live. What i can buy is this:

sera ammonium/ammonia-Test (NH4/NH3) | sera

sera NH4/NH3-Test - Water test for aquariums ✔ checks aquarium water for ammonium and ammonia ✔ optimize water parameters ✔ Find out more now!

www.sera.de

Or this:

JBL NH4 Ammonium Test

Checks the biological balance (bacterial activity) in freshwater and marine water

www.jbl.de

I am reading the sticky right now and i will see what conditioner i can find at my local pet store.

Ideally, you need a liquid test kit that will test for ammonia, nitrIte, nitrAte, and ph...hopefully some other members can make suggestions for what may be available to you

 

[Bicyclemaster]

Olay so what I gathered from the cycling sticky si that, by adding bacteria i will be able to speed up the cycling process drastically, but at the same time i have to keep a close eye on the NH3 and nitrites and if there is a spike to take care of it with water changes or salt for nitrites. I hope i got all of the important thongs down.

Thank you again for helping me fix my mistake.

 

[Bruce Leyland-Jones]

This friend of mine who has been wlrking in the fish industry for 20 years told me that i could cycle the aquarium with only the plants and it would also be faster. Sadly i did the mistake of listening to him.

Actually, he was correct.

I have one last question: once i am done with the cycle i want to add corys again so, how many at a time can i add as to not create an ammonia or nitrite spike?

It would be best to wait until your tank is definitely cycled, before adding any fish. Patience is the key.
When your beneficial bacteria have grown so that they can absorb ammonia, then you could add a group of up to 5 corys. (In theory, some would argue that you can fully stock your tank at this point. I'd argue against this as strongly as I can. Even though your tank may be 'cycled', the bacteria could become overwhelmed, with catastrophic consequence. It's just not worth rushing things, even at this late stage).
When you do add any fish, you should keep an eye on the ammonia, nitrite and nitrate levels and if you ever get more than zero for the first two, then you should do a 30-50% water change.

Back to your friend, if you had plants in the tank, then this would've been both safer and easier, (in my opinion, based on decades of good experiences and those of aquarist mates). Plants are great at absorbing ammonia in the tank. Floating plants are especially good at helping to manage nitrites/nitrates.

Olay so what I gathered from the cycling sticky si that, by adding bacteria i will be able to speed up the cycling process drastically...

Remember that cycling a tank is all about growing a useful population of beneficial bacteria. There are some good bottled bacteria now available and these can save some time, but problems arise when some view these as a 'quick fix' and rush the process. Things then go badly wrong and the failed fishkeeper then blames the bottled bacteria on their failure.

...but at the same time i have to keep a close eye on the NH3 and nitrites and if there is a spike to take care of it with water changes or salt for nitrites. I hope i got all of the important thongs down.

Correct with the water changes, which can help solve most of the problems you'll ever come across in keeping fish.
Not sure about 'salt for nitrites'.

 

[Bicyclemaster]

Hey Bruce, thanks for the feedback.

I'm glad that there is someone who is used to plant cycling. Since everybody was telling me that the plants didn't help with the cycle, i started thinking that it was the truth. I'm pretty sure rhe the tank cycled a bit, since there were 1ppm nitrites before i did the water change today. As for the bacteria, i'm not trying to rush anything, i'm listening to the instructions on the bottle. The idea that salt helps with nitrites was written on this forum on the post related to in-fish cycling.

 

[Myraan]

If you start to find all the testing boring that will be a good thing because if the results are not interesting to you the water is probably good for the fish.

 

[Essjay]

The Sera or JBL ammonia and nitrite testers are both OK. Ammonia and nitrite are the killers so you need to be able to test for both of them. Nitrate and pH are useful but if you can't afford them as well, get just ammonia and nitrite.