Cories seem to be gradually wasting away

[anikom15]

I have a planted 20 gallon that originally had six male guppies (in hindsight this was a mistake; they bicker often), nine fales julii corydoras, a nerite snail, and many bladder snails. The tank developed a green water problem which made it near impossible to observe the fish, so I got a UV sterilizer and it cleared up. I continued to run the UV sterilizer when one cory, who was the smallest and never really thrived in the tank, developed a swim bladder issue and continually slept on his side. Eventually he passed away from what I assume was starvation, as he had a dimple under his belly. He had no other visible symptoms. A few days before, however, a guppy died suddenly. There were no visible symptoms and he was acting normally the day before he died. He was also the smallest. I wrote off these two deaths as 'runt' deaths (and possibly old age for the guppy, as I've had him for a few months). The day he died I put the UV sterilizer on a timer as I no longer needed it to run 24 hours with the green water gone.

A couple days after the first cory finally died, a second cory got sick. She developed a bit of extra mucus on her coat, and would keep her fins clamped. The day before she died she would shimmer, but didn't have swim bladder issues. The day she died (yesterday) she began turning over and her dorsal fin deteriorated quickly. She also had some very small red blotches on her front, and the characteristic stomach dimple from lack of eating.

The day before the second cory died, another cory developed a 'corkscrew' tick, but after I changed the water (25%) she was fine. The day after, a completely different male cory appears to have a swim bladder issue, again sleeping on its side. As before, there are no visible signs of illness. He doesn't even breathe rapidly. I'm at a loss at what the problem could be, but since this is likely going to be the fourth death of the tank, I need to try to figure this out.

Right now I have Ich-X and ParaCleanse. I ordered Maracyn 1 and 2 but it will take a while to get. Yesterday I treated the tank with ParaCleanse, as parasites are my prime suspect. I assume that the red blotches were a secondary bacterial infection due to stress from the parasites or injury. Right now, the cory that developed the swim bladder issue is alive but on its side and will likely die. The other cories are resting. They don't seem stressed, but they also don't seem themselves. They have energy, as when they do decide to move, they move quickly, and do their normal foraging thing. My assumption is that they are bothered or cautious about the medicine that was added to the tank, and perhaps because of the new flow from an air stone I added when I started the ParaCleanse. I also didn't feed them today.

The UV sterilizer is off (but still in the tank) so as to not interfere with the ParaCleanse.

I never did quarantine tanks before, but I think I will be doing that going forward...

Water parameters (taken this morning):

• 20 gallon
• pH - 7.6+ (API pH test, I ordered the High Range pH test, but it could be as high as 8.0 according to my tap water reports)
• Nitrates - (0, floaters keep it at 0 constantly)
• Hardness - ~300 ppm (according to test strip, but I orderd the GH/KH API test for better test; tap water reads 0 GH so I use wonder shells to raise this)
• Nitrite - 0
• Ammonia - 0
• KH/Buffer - ~40 ppm (test strip, tap water is very high KH. Something caused the KH to drop quickly since the green water went away)
• Water Temperature - 75
• Sand substrate
• HOB filter + airstone

I recently read that cories don't like high pH water. I didn't know the water was so high in pH until I used the API test kit (never use Amazon off-brand test strips!), but I also read that they don't like high GH water. There is a lot of contradicting information about this. If the wonder shell is bothering them, I'm wondering if aragonite or crushed coral will be able to provide calcium without as strongly affecting GH as the wonder shell.

Summary:

• Corydoras died from swim bladder and starvation, a second is dying this way
• A different corydoras died after shimmying, red blotches, and fin rot.
• A guppy died for seemingly no reason
• Guppies are acting normal; cories are cautious, but retain energy

[anikom15]

Here are some pictures I just took. The first two is the sick fish. The last is one of the healthy ones.

Edited April 22, 2023 by anikom15

[Tommy Vercetti]

If your water is as hard as indicated, I doubt you need to add calcium at all. Gh is mostly calcium and magnesium. 

I would remove the Wonder shell. But my tap water is hard water.

[Tommy Vercetti]

What is your water change schedule like?

 

[anikom15]

On 4/21/2023 at 1:46 PM, Tommy Vercetti said:

What is your water change schedule like?

 

Recently I’ve been doing a 25% change per week. I did a WC just before dosing ParaCleanse.

[Tommy Vercetti]

What was the schedule before all of this happened? I like the 25% water change weekly for now, until you see how that goes. 

[anikom15]

About every two weeks.

[Colu]

With the sunken bellys and some of the other symptoms your describing possible wasting disease you would want to treat with Fritz Expel p active ingredient levamisole once week for 4 weeks @anikom15

[anikom15]

The third corydoras died this afternoon. I think I got him out of the tank pretty fresh. The other fish are still acting normal.

[nabokovfan87]

Getting the PH stable will be helpful.  Sometimes corydoras just have issues and it's extremely frustrating.  I have had it happen and both times it was difficult on me to know why.  Mostly on the final batch of corydoras (my blacks) I spent far too much time not realizing what they needed.  First, sub 7.5 PH water, when it got to high mine turned red. Just means don't get too carried away with the KH buffers.  Secondly, they need food that are easy for them to eat and accessible (video below).  Finally, they need the right temp/oxygenation mix.  As temps go up, add more oxygen. 

 

On 4/21/2023 at 1:30 PM, anikom15 said:

Overall the fish looks fine.  I don't see any severe signs of stress or issues.

 

On 4/21/2023 at 11:16 AM, anikom15 said:

Water parameters (taken this morning):

• 20 gallon
• pH - 7.6+ (API pH test, I ordered the High Range pH test, but it could be as high as 8.0 according to my tap water reports)
• Nitrates - (0, floaters keep it at 0 constantly)
• Hardness - ~300 ppm (according to test strip, but I orderd the GH/KH API test for better test; tap water reads 0 GH so I use wonder shells to raise this)
• Nitrite - 0
• Ammonia - 0
• KH/Buffer - ~40 ppm (test strip, tap water is very high KH. Something caused the KH to drop quickly since the green water went away)
• Water Temperature - 75
• Sand substrate
• HOB filter + airstone

HoB might be undersized.  Temp is perfectly fine, everything else looks fine apart from PH.  It is slightly too high.  Here is an article to help with what you're dealing with and the use of wondershells, crushed coral, equilibrium, and others.

https://www.aquariumcoop.com/blogs/aquarium/ph-gh-kh

My advice right now would be a 50-80% water change, get your water a bit closer to your tap and to add an airstone to the tank.  (HOB in the middle, air on either side with the use of a gang valve).  Monitor parameters over the next two weeks and let us know how things change.  With regards to your KH, I would expect PH to be lower (at or near 7.0).  Once you get in all the new tests it might be more clear as to what is going on.

[nabokovfan87]

As mentioned above, the bloating issues, added mucous layer might point towards parasites in the water of some kind.  This batch might simply need some parasite meds.  I'll attach a video for that as well.
 

 

[anikom15]

On 4/21/2023 at 7:18 PM, nabokovfan87 said:

Getting the PH stable will be helpful.  Sometimes corydoras just have issues and it's extremely frustrating.  I have had it happen and both times it was difficult on me to know why.  Mostly on the final batch of corydoras (my blacks) I spent far too much time not realizing what they needed.  First, sub 7.5 PH water, when it got to high mine turned red. Just means don't get too carried away with the KH buffers.  Secondly, they need food that are easy for them to eat and accessible (video below).  Finally, they need the right temp/oxygenation mix.  As temps go up, add more oxygen. 

 

Overall the fish looks fine.  I don't see any severe signs of stress or issues.

 

HoB might be undersized.  Temp is perfectly fine, everything else looks fine apart from PH.  It is slightly too high.  Here is an article to help with what you're dealing with and the use of wondershells, crushed coral, equilibrium, and others.

https://www.aquariumcoop.com/blogs/aquarium/ph-gh-kh

My advice right now would be a 50-80% water change, get your water a bit closer to your tap and to add an airstone to the tank.  (HOB in the middle, air on either side with the use of a gang valve).  Monitor parameters over the next two weeks and let us know how things change.  With regards to your KH, I would expect PH to be lower (at or near 7.0).  Once you get in all the new tests it might be more clear as to what is going on.

The airstone is a recent addition and the fish already seem to prefer having it. I originally didn’t put one in because of the noise, but I’m getting one of those mini air pumps and hopefully it will be quiet enough to not bother me. The actual bubble noise doesn’t bother me, just the vibrations of the pump. I’ll ditch the wondershell and see how the GH/KH/pH settles with straight tap.

[nabokovfan87]

On 4/21/2023 at 11:06 PM, anikom15 said:

The actual bubble noise doesn’t bother me, just the vibrations of the pump.

You can cover it or put it on top of a towel. I have rubber pads I use as well as a folded up hand towel.  All you have to be sure is that you have a piece of something hard/flat for wherever the air filter is so that it doesn't suck up lint.

Or there's this.....
 

Some are louder than others....

[anikom15]

Today is day five of ParaCleanse treatment so I did a 25% water change, replaced polishing floss into the filter, converted the airstone into an airstone+sponge (to have a QT filter on hand when needed) and turned the UV sterilizer back on. I will keep the sterilizer on 8 hours per day for a week to prevent green water, and then decommission it.

Before the water change, one of the cories had a partially clamped fin and wasn’t moving much, but after acclimating to the new water and feeding, he is moving again. It seems like the males are more sensitive to whatever is happening in the tank than the females.

I’ll do another water change on Wednesday. Two things have begun happening recently:

The tank has developed an earthy smell (cyanobacteria?)

The plants and walls are starting to get hair algae.

I assume these had an opportunity to growth with the gap in green water, but these two algae types at least still allow me to see my fish.

Another weird issue is that this tank develops foam on the edges of the water. The foam never builds up, but it’s there. I never test positive for ammonia, so I’m at a loss for what it could be. Whenever I water change, the foam disappears for a bit, but builds up again in a couple days.

I’ll post another update on the water change Wednesday.