Corydoras wont stop dying

[bianca_m35]

Sooo I'm really starting to get frustrated. I had 9 panda Cory's, 6 peppered corys, and 6 bronze corys. I'm left 5 bronze and 1 peppered Cory. Well I got 5 new peppered corys and now one of my bronze corys died. So peppered corys and 4 bronze at the moment.

They eat a very big range of foods, blood worms, veggies, flakes, egg, etc.

The water parameters are

Ammonia 0
Nitrite 0
Nitrate 10
Ph 7.6
Water hardness 7

They're all extremely active and healthy, as well as eating a ton. Until I just wake up and they're dead. There's no parasites or illness either.

It's a planted tank as well

Temp is 73

Gravel and rock for substrate

I really have no clue what is going on. And it's only the corydoras dying, literally all of my other fish are fine and I had my corys for about a year now and got them all pretty young.

Other tank mates, 1 kuhli loach, 2 rainbow sharks that don't touch the corys at all, 2 red bristlenose plecos that are still young and don't go near the corys unless eating but they eat algae wafers or stems, while the corys eat the smaller bits, and now I have 4 cherry barbs who are juveniles. As well as a bunch if baby snails. They've been dying way before the cherry barbs or snails came into the tank. Their bodies when dead have no marks on them either.

 

[itiwhetu]

I think your pH is to high for Cory's. The rainbow sharks are most probably not helping either.

 

[Byron]

Genetic problems with the fish is always a possibility, but the rapid rate of death you describe would not lead one to assume genetic, so we need to look further.

Water hardness at 7, is that 7 dH or 7 ppm? Just to clarify that.

Gravel is not a suitable substrate for cories, but that in itself is not likely to cause the rapid deaths, but gravel can cause serious bacterial issues especially for substrate fish. Do you vacuum into the substrate at water changes, and how frequent and what volume are water changes?

The foods can be issues sometimes. Bloodworms should not be fed more than once a week, and frankly it would be better to not feed them at all. Fluval's Bug Bites is one of the best cory foods as it is exactly what they at in their habitats--insects and insect larvae. Shrimp pellets are another good food. Frozen daphnia is another.

Another possible issue would be the Rainbow Sharks. These should not be combined with other substrate fish, especially cories. You may or may not see issues between them, but they can still be occurring in darkness.

 

[itiwhetu]

A photo of your tank may help us to see other problems.

 

[AdoraBelle Dearheart]

Yes, please share some photos of the tank, and of the cories if possible!

If you drop some shrimp pellets or an algae wafer or something at the front of the tank, that can help gather the cories together to snap some photos.

ETA: When was the last water test? Do you test the water after every death?

 

[Avel1896]

rainbow sharks

You really should rehouse rainbow sharks as they can turn extrement aggressive and territorial. Also they grow big. What are tank measurements ? Moreover, there are too many bottom and mid-level dwellers : Cories + Pangio khuli + rainbow sharks = at best squabbles, at worst rainbow shark aggressiveness leading to high stress in Cories and sadly, their death.
In addition pH is too high but I doubt it is deaths cause.

 

[bianca_m35]

Yes, please share some photos of the tank, and of the cories if possible!

If you drop some shrimp pellets or an algae wafer or something at the front of the tank, that can help gather the cories together to snap some photos.

ETA: When was the last water test? Do you test the water after every death?

Yes I've been water testing every time and I just did and the levels are perfect. My fish are literally dropping dead every one of them. I don't know what's happening my loach, female cherry barb, peppered Cory, and a bronze cory are dead now I just looked. They're eating some veggies let me get a picture. I've had this tank for over a year with no issues now they're just dying?

 

[bianca_m35]

Genetic problems with the fish is always a possibility, but the rapid rate of death you describe would not lead one to assume genetic, so we need to look further.

Water hardness at 7, is that 7 dH or 7 ppm? Just to clarify that.

Gravel is not a suitable substrate for cories, but that in itself is not likely to cause the rapid deaths, but gravel can cause serious bacterial issues especially for substrate fish. Do you vacuum into the substrate at water changes, and how frequent and what volume are water changes?

The foods can be issues sometimes. Bloodworms should not be fed more than once a week, and frankly it would be better to not feed them at all. Fluval's Bug Bites is one of the best cory foods as it is exactly what they at in their habitats--insects and insect larvae. Shrimp pellets are another good food. Frozen daphnia is another.

Another possible issue would be the Rainbow Sharks. These should not be combined with other substrate fish, especially cories. You may or may not see issues between them, but they can still be occurring in darkness.

7 dh and now 3 more fish just died. Ughhh what is going on? I'm posting a picture

 

[AdoraBelle Dearheart]

Yes I've been water testing every time and I just did and the levels are perfect. My fish are literally dropping dead every one of them. I don't know what's happening my loach, female cherry barb, peppered Cory, and a bronze cory are dead now I just looked. They're eating some veggies let me get a picture. I've had this tank for over a year with no issues now they're just dying?

I'd suggest an emergency water change - but need to know roughly how often you do a water change and how much of the tank volume you change each time, before you do so, and beforeadvising what emergency steps to take next!

E.g: 20% monthly or 50% weekly, whatever your usual schedule is.

 

[bianca_m35]

Sooo I'm really starting to get frustrated. I had 9 panda Cory's, 6 peppered corys, and 6 bronze corys. I'm left 5 bronze and 1 peppered Cory. Well I got 5 new peppered corys and now one of my bronze corys died. So peppered corys and 4 bronze at the moment.

They eat a very big range of foods, blood worms, veggies, flakes, egg, etc.

The water parameters are

Ammonia 0
Nitrite 0
Nitrate 10
Ph 7.6
Water hardness 7

They're all extremely active and healthy, as well as eating a ton. Until I just wake up and they're dead. There's no parasites or illness either.

It's a planted tank as well

Temp is 73

Gravel and rock for substrate

I really have no clue what is going on. And it's only the corydoras dying, literally all of my other fish are fine and I had my corys for about a year now and got them all pretty young.

Other tank mates, 1 kuhli loach, 2 rainbow sharks that don't touch the corys at all, 2 red bristlenose plecos that are still young and don't go near the corys unless eating but they eat algae wafers or stems, while the corys eat the smaller bits, and now I have 4 cherry barbs who are juveniles. As well as a bunch if baby snails. They've been dying way before the cherry barbs or snails came into the tank. Their bodies when dead have no marks on them either.

That's the best I can get my tank is 50 gallons

 

[bianca_m35]

I'd suggest an emergency water change - but need to know roughly how often you do a water change and how much of the tank volume you change each time, before you do so, and beforeadvising what emergency steps to take next!

E.g: 20% monthly or 50% weekly, whatever your usual schedule is.

I do 25% weekly and 50% monthly

 

[AdoraBelle Dearheart]

I do 25% weekly and 50% monthly

In that case, I'd advise that you do an emergency water change right now, change at least 50-70% of the total tank volume. Make sure to use water conditioner and temperature match the new water to the tank temperature before adding it in to the tank.

Let us know once that's done, and then I'll go into more detail about what I suspect is happening.

When you do the water change, don't try to clean the filter or anything, just fresh clean water to try to save the remaining fish

 

[AdoraBelle Dearheart]

This really is urgent. If it's what I suspect it is, then every minute without a water change is another minute of the fish suffering burning gills...

Once we've reduced that risk with a water change (and using Prime water conditioner if you have it on hand!) then we can talk and figure out what the problem is

 

[bianca_m35]

This really is urgent. If it's what I suspect it is, then every minute without a water change is another minute of the fish suffering burning gills...

Once we've reduced that risk with a water change (and using Prime water conditioner if you have it on hand!) then we can talk and figure out what the problem is

I almost have it at 50% emptied but I'm probably going to do 70% just to be safe. I only have a Nitrite and ammonia conditioner that's it at the moment. Can the burning gills kill off other fish? ☹

 

[AdoraBelle Dearheart]

I almost have it at 50% emptied but I'm probably going to do 70% just to be safe. I only have a Nitrite and ammonia conditioner that's it at the moment. Can the burning gills kill off other fish? ☹

It can, yes But a large water change will hopefully prevent any more losses, and buy us some more time to figure things out! Well done for getting right on it

That's okay, just use your usual ammonia and nitrite conditioner

Which brand and type of test kit have you been using for your water parameters?