Corydoras wont stop dying

Thr corys grabbed to much air when I was filling it up, that they all keep floating 🤦🏽‍♀️ I'll give it a few hours and they'll be fine, this happens sometimes when I do a big water change.
They're all okay now :) only one is floating but starting to less

This needs to be looked into. Corydoras fish should never be floating after a water change, nor even be near the surface. I suspect that whatever is behind this is the issue. This could be one of several issues.

I mentioned that bacterial problems with gravel were dangerous for cories. Do you dig into the gravel to vacuum it during the water changes? I know you said you did this time, but what about previous water changes?

What are the GH and pH of the source (tap) water, compared to the tank water? If there is a significant difference, this might be the issue (or part of it).
 
Corydoras fish should never be floating after a water change, nor even be near the surface
Digestive process issue like constipation ? Preventing their intestine breathing system to expel oxygen they took at surface ?
 
I have a cartridge filter that I replace once a month, I use just hot water and a never used Toothbrush to clean it. I can't remember the specific brand.
I am sorry to hear about your fish :(

Changing your filter cartridge once a month is not necessary, they can and should last months unless they are falling apart. Your filter materials should be cleaned every 6-8 weeks using water straight from the tank (no tap water at all) in a clean bucket in which no chemicals are present. Throw the dirty water out from the bucket and place the cartridge back in the system.
 
Like Byron mentioned I think it is the food and the lack of certain minerals / vitamins / proteins. Add shrimppellets to their diet and stop feeding egg. Vegs won't hardly provide any nutritional value for corys.
 
@bianca_m35 cories are 80% carnivorous for only 20% vegetarian fishes.
Vegetarian food once a week is enough. The rest of time give them a 38/40% animal protein sinking food.
 
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Going to throw my hat into the ring here....my thoughts on this enigma are...

Temp is too low. The average - if this were my aquarium - would be 75 and not 73....two degrees can make a lot of difference when health is a question.

pH is not compatible for the mix of fish that you have..the Cories will handle a wide range pH and your's is at the top end of the range, Cherry Barbs again top end of their range if a little above it, BN's are OK, Rainbow Sharks are a smidgen above their normal range, Khuli Loach is on the high end if not over top of their range

Planting is definitely unsuitable....you need to have multiple sight blocks (ie clumps of thick planting that will stop one fish from seeing another) absolutely vital when you have aggressive fish such as the Sharks. Also things like caves, wood, rocks to act as santuary for bullied fish (just cos you might not see bullying does not mean that its not happening as much of it is at night/lights off). You should also have a sandy area for the Cories to sand snuffle and the Kuhli to burrow into.

I suspect that your fish deaths have something to do with the combination of stock, excessive bullying by the Sharks and your lower aquarium is overcrowded, species wise, and they are fighting over food. Despite looking like they are quite tough, the Cories are not great at learning about territory and since the Sharks are hyper territorial there is every chance that the Sharks have literally harrassed and chased the Cories to death. It happens more than people realise. The deaths of your Cories will be due to a multitude of things, a perfect storm of water chemistry, poorly chosen/aggressive tankmates, insufficient planting/scaping to allow fish to hide and relax, substrate not really being right and just too many species all fighting for space and food on the lower regions of the aquarium.

I would suggest that you decide what you want to keep and rehome the rest.....such as rehome both of the Sharks and one BN. I would then add a few more Khuli's since they are not lone fish, they like company to thrive. I would maybe add a few more Cherry Barbs as they tend to get nervy in small numbers.

Your top priority is rehoming the aggressive fish and a BN, the water chemistry, the filter servicing (no need to change filter pads monthly, wait til they fall to bits), the planting and aquascaping. I would also suggest you purchase a small air pump, airline and airstone cos thats alot of water without an ancilliary oxygen supply.....and the regular surfacing of Cories is indicative of an oxygenation issue.

JMO.
 
Going to throw my hat into the ring here....my thoughts on this enigma are...

Temp is too low. The average - if this were my aquarium - would be 75 and not 73....two degrees can make a lot of difference when health is a question.

pH is not compatible for the mix of fish that you have..the Cories will handle a wide range pH and your's is at the top end of the range, Cherry Barbs again top end of their range if a little above it, BN's are OK, Rainbow Sharks are a smidgen above their normal range, Khuli Loach is on the high end if not over top of their range

Planting is definitely unsuitable....you need to have multiple sight blocks (ie clumps of thick planting that will stop one fish from seeing another) absolutely vital when you have aggressive fish such as the Sharks. Also things like caves, wood, rocks to act as santuary for bullied fish (just cos you might not see bullying does not mean that its not happening as much of it is at night/lights off). You should also have a sandy area for the Cories to sand snuffle and the Kuhli to burrow into.

I suspect that your fish deaths have something to do with the combination of stock, excessive bullying by the Sharks and your lower aquarium is overcrowded, species wise, and they are fighting over food. Despite looking like they are quite tough, the Cories are not great at learning about territory and since the Sharks are hyper territorial there is every chance that the Sharks have literally harrassed and chased the Cories to death. It happens more than people realise. The deaths of your Cories will be due to a multitude of things, a perfect storm of water chemistry, poorly chosen/aggressive tankmates, insufficient planting/scaping to allow fish to hide and relax, substrate not really being right and just too many species all fighting for space and food on the lower regions of the aquarium.

I would suggest that you decide what you want to keep and rehome the rest.....such as rehome both of the Sharks and one BN. I would then add a few more Khuli's since they are not lone fish, they like company to thrive. I would maybe add a few more Cherry Barbs as they tend to get nervy in small numbers.

Your top priority is rehoming the aggressive fish and a BN, the water chemistry, the filter servicing (no need to change filter pads monthly, wait til they fall to bits), the planting and aquascaping. I would also suggest you purchase a small air pump, airline and airstone cos thats alot of water without an ancilliary oxygen supply.....and the regular surfacing of Cories is indicative of an oxygenation issue.

JMO.
Okay I'll change all of that. So since I will only have 3 cherry barbs (which have laid eggs, so I'll have more) 7 corys, 1 BN, and the baby snails, what do you recommend? I'll get a few more corys, so the peppered and bronze corys have 6 in each group. I'll group the plants together more as well. But that water change helped I have no more dead fish at least :)
 
Okay I'll change all of that. So since I will only have 3 cherry barbs (which have laid eggs, so I'll have more) 7 corys, 1 BN, and the baby snails, what do you recommend? I'll get a few more corys, so the peppered and bronze corys have 6 in each group. I'll group the plants together more as well. But that water change helped I have no more dead fish at least :)
Your proposed numbers for the Corys sounds better, but you have way too few Cherry Barbs for them to thrive. Assuming that their eggs will turn into fish is a bit of a long shot, especially given that stressed barbs may well nosh on their young.
 
Going to throw my hat into the ring here....my thoughts on this enigma are...

Temp is too low. The average - if this were my aquarium - would be 75 and not 73....two degrees can make a lot of difference when health is a question.

pH is not compatible for the mix of fish that you have..the Cories will handle a wide range pH and your's is at the top end of the range, Cherry Barbs again top end of their range if a little above it, BN's are OK, Rainbow Sharks are a smidgen above their normal range, Khuli Loach is on the high end if not over top of their range

Planting is definitely unsuitable....you need to have multiple sight blocks (ie clumps of thick planting that will stop one fish from seeing another) absolutely vital when you have aggressive fish such as the Sharks. Also things like caves, wood, rocks to act as santuary for bullied fish (just cos you might not see bullying does not mean that its not happening as much of it is at night/lights off). You should also have a sandy area for the Cories to sand snuffle and the Kuhli to burrow into.

I suspect that your fish deaths have something to do with the combination of stock, excessive bullying by the Sharks and your lower aquarium is overcrowded, species wise, and they are fighting over food. Despite looking like they are quite tough, the Cories are not great at learning about territory and since the Sharks are hyper territorial there is every chance that the Sharks have literally harrassed and chased the Cories to death. It happens more than people realise. The deaths of your Cories will be due to a multitude of things, a perfect storm of water chemistry, poorly chosen/aggressive tankmates, insufficient planting/scaping to allow fish to hide and relax, substrate not really being right and just too many species all fighting for space and food on the lower regions of the aquarium.

I would suggest that you decide what you want to keep and rehome the rest.....such as rehome both of the Sharks and one BN. I would then add a few more Khuli's since they are not lone fish, they like company to thrive. I would maybe add a few more Cherry Barbs as they tend to get nervy in small numbers.

Your top priority is rehoming the aggressive fish and a BN, the water chemistry, the filter servicing (no need to change filter pads monthly, wait til they fall to bits), the planting and aquascaping. I would also suggest you purchase a small air pump, airline and airstone cos thats alot of water without an ancilliary oxygen supply.....and the regular surfacing of Cories is indicative of an oxygenation issue.

JMO.
Okay I'll change all of that. So since I will only have 3 cherry barbs (which have laid eggs, so I'll have more) 7 corys, 1 BN, and the baby snails, what do you recommend? I'll get a few more corys, so the peppered and bronze corys have 6 in each group. I'll group the plants together more as well. But that water change helped I have no more dead fish at least
Your proposed numbers for the Corys sounds better, but you have way too few Cherry Barbs for them to thrive. Assuming that their eggs will turn into fish is a bit of a long shot, especially given that stressed barbs may well nosh on their young.
The eggs are in a breeder box. Most are fertilized as well. :)
 
This is not getting you or us very far. There are obvious issues concerning the "floating" by cories at every water change which nothing so far has addressed. The questions I asked in post #31 need to be answered if we are to get to the cause.
 

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