Help. Cory keeps lying on its side

Im going to try and keep this short than fill the full template. My water parameters are perfect with ammonia and nitrite and nitrate. Ph is 6.8. It's a 125L fluval roma tank. Well maintained. Between 30% and 40% water changed weekly. I lost corys when I tried to raise my pH for my snails. I now know they prefer softer water. So since losing them corys, 2 survived out of 6. I got 3 new ones. All the 3 new ones died. So I used fluke solve which is uks version of prazi Pro. After dosing put carbon in. I then added another 3 corys so I had six in total. Then added prazi again three weeks later. Then added carbon again. Now about six weeks later a cory is doing the same as the others. Just very lethargic. Not eating. Gets to where they struggle to keep upright and lie on their side. Eventually they die. I feel like I now don't know what to do. The water is stable and perfect for corys. I used the fluke solve because its a good med that isn't harsh on the tank. Since moved my snails back. I'm considering moving my snails and adding aquarium salt. I know corys don't tolerate salt well tho. Im starting to think their is something bacterial going on. Anyone any ideas?

 

I’d scroll through this earlier post/thread there are some good replies from other Cory keepers. Sounds like they sensitive to ph and temperature issues.

Cory Cat Fish Not Surviving. Low Ph? | Freshwater Fish Disease and Fish Health Forum | 360489

Is the ph 6.8 in the tank or straight from the tap? I’d suggest testing them side by side to see if significant difference. If so do smaller volume water changes. If not that much different at least you could cross if off as problem.

Best of luck!

Im going to try and keep this short than fill the full template. My water parameters are perfect with ammonia and nitrite and nitrate. Ph is 6.8. It's a 125L fluval roma tank. Well maintained. Between 30% and 40% water changed weekly. I lost corys when I tried to raise my pH for my snails. I now know they prefer softer water. So since losing them corys, 2 survived out of 6. I got 3 new ones. All the 3 new ones died. So I used fluke solve which is uks version of prazi Pro. After dosing put carbon in. I then added another 3 corys so I had six in total. Then added prazi again three weeks later. Then added carbon again. Now about six weeks later a cory is doing the same as the others. Just very lethargic. Not eating. Gets to where they struggle to keep upright and lie on their side. Eventually they die. I feel like I now don't know what to do. The water is stable and perfect for corys. I used the fluke solve because its a good med that isn't harsh on the tank. Since moved my snails back. I'm considering moving my snails and adding aquarium salt. I know corys don't tolerate salt well tho. Im starting to think their is something bacterial going on. Anyone any ideas?

Also are you running air? Sponge filter/air stone? If you have a planted tank it could be lower night time oxygen levels in tank. Plants can complete/deplete at night. Just more process of elimination.

 

Yes it's 6.8 from the tap. Very low kh. I have a small amount of crushed coral in the filter to keep kh at 2 as previously I've had ph drop to below 6. All my corys and danios survived that ph drop. My snails were foaming and bubbling so I buffered the ph to 7 using crushed coral. Its now enough to keep it at 6.8. I also add the water of an hour period when water changing

I'm losing corys roughly once every 4 to 6 weeks. I has six originally. Ended up losing 3 when I tried messing with my pH. Naivety and a schoolboy error. Tried adding equilibrium and alkaline buffer to keep ph at 7.2 for my snails. It's 6.8 out the tap and very soft water. Kh 1 and gh 3. Anyway over the course of a month I changed my water back to just out the tap. Only adding dechlorinator and nothing else

I got another 3 corys from pets at home. Within 2 months all of them had died. So I ran carbon in the tank for 6 six weeks. Then I got another 3 from a very popular, reputable fish shop near me. Then one of the original 3 left died. So I used fluke solve which is uks version of prazi pro. Doesn't harm the tank or biomedia. I moved all my snails to my shrimp tank while doing this. Then I ran carbon again for 3 weeks then dosed fluke solve again. Then ran carbon again. I've since lost another 2 fish. Six weeks after the final dose of fluke solve and another one is showing the same symptoms. They go very lethargic. Just staying at the bottom and not moving. But also can't keep upright. I change 30% of the water every week and gravel vac the sand

I also lost a danio a few weeks ago but something had shredded its fin. It must have have attacked by another fish. My stock is danios and corys. I'm guessing their has to be a disease. Bacterial maybe. I just feel totally stuck and powerless

 

I think completing the emergency template would help here, to save you being asked multiple questions and to give a better understanding of your tank conditions. Pictures of the tank and fish may also help out too.

 

I did another thread yesterday. I can tell you all the parameters as in ammonia and nitrite and nitrate are 0. Water changed weekly between 30% and 40%. Water added over an hour. Not dripped I but slower than just pouring in. Temp is 24C/75F. Tank is a fluval roma 125L with 11 danios, 4 corys but one is definitely going to die. Peppered corys by the way. And about 6 nerite snails
Tank
What is the water volume of the tank? 125L/100L of water
How long has the tank been running? 2 Years
Does it have a filter? Fluval U3
Does it have a heater? Yes
What is the water temperature? 24C/75F
What is the entire stocking of this tank? (Please list all fish and inverts.) 2 zebra danios, 1 leopard danio, 2 pearl danios, 6 glowlight danios, 4 peppered corys, 7 nerite snails

Maintenance
How often do you change the water? Once a week
How much of the water do you change? Roughly 30%, sometimes 40%
What do you use to treat your water? Seachem Prime
Do you vacuum the substrate or just the water? Vac sand weekly

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water? API Master Test Kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.
Ammonia: 0
Nitrite: 0
Nitrate: Below 5
pH: 6.8

Feeding
How often do you feed your fish? Five times a week
How much do you feed your fish? Enough to eat in a minute
What brand of food do you feed your fish? Hikari pellets, hikari algae wafers, catfish pellets, tetra flake
Do you feed frozen? Once a month
Do you feed freeze-dried foods? Once a month

Illness & Symptoms
How long have you had this fish? Three months
How long ago did you first notice these symptoms? Yesterday
In a few words, can you explain the symptoms?
Have you started any treatment for the illness?
Was your fish physically ill or injured upon purchase? No
How has its behavior and appearance changed, if at all? No

Explain your emergency situation in detail.
(Please give a clear explanation of what is going on, include details from the beginning of the illness leading up to now)

Please read start of thread for explanation on illness. Lethargic. Can't keep upright unless propped up against glass or ornament or plant. All other catfish showed same symptoms. Lost a few danios. Danio symptoms, sunken belly, lethargic

 

Nothing stands out to me as an obvious issue. Are the corys definately getting enough food? I know algae wafers aren't nutritious for them but the catfish pellets should have enough protein.

The issue could be the danios. Other than the glow lights the zebra, leopard and Pearls would appreciate more numbers. My experience is despite being very similar fish they don't always form a schoal together.

Low numbers can lead to aggressive behaviour with danios. I've known them to kill each other! Being such voracious eaters the danios could be hoovering up any before it gets to the corys? Unlikely but trying to think of possibilities.

If it's an internal illness I wouldn't know what to do exactly. Often treating without knowing causes more stress and fish losses. I would also accept you PH and pick soft water species or gradually buffer it with a bag of crushed coral in your filter. Hope you can get it sorted.

 

I was planning on getting another 1 zebra and 2 leopards. The zebra and leopard are the same species. Your right danios are like piranhas lol I tend to feed the corys a lot later on when it's dark. When it's dark the danios can't see the food. But I've had no issues with my previous six. I had them for a year before I tried messing with the pH. I have a small amount of crushed coral in the filter. My pH dropped to below 6 a good while ago. I added crushed coral then to stabilise it a lot more. The water is incredibly soft so it gives it a bit more buffering capacity. I just feel stuck. I lost danios last year. Those fish are bulletproof so I should have suspected illness then. Treated with fluke solve and everything was OK. I'm currently cycling a tank for my shrimp and snails. All my invertebrates will be in that in the next 2 months. I have melafix and I have interpet anti internal bacteria meds to hand
Here is a healthy cory and the one who's not so good. Very fast breathing now. It's frustrating this keeps happening

 

First time what jumps in mind is change the diet. Most food is more on the herbivorious side of the spectrum. Corys are not. Tetra is fastfood.
Looks like what I call Algaewaferitis.
Feed shrimppellets, more frozen etc....

 

Il find out what I give them mostly. It's catfish pellets. They're really small. Actually has a peppered cory on the cover
Vitalis the brand is called. Catfish bottom feeding sinking pellets