55 Gallon Tank 2 corydoras died after HUGE cleanup, Kuhli now looks weird?

Background
On May 3th my filter broke but at that time I was unable to maintain regular schedules for the aquarium. I added an air pump. On May 4th I installed an Aquaclear 50 that was in storage. On may 5th I did a huge clean up of the tank - read details below. On May 6th one of our Peppered Cory died, on May 7th the second one died.



I noticed tonight that my 4 Kuhlis have kind of huge bellies. Red-ish gills, two of them have pink bellies. All 4 are glass surfing all the time and they all seems to be eating. I'll be feeding them Brime Shrimp tomorrow in case of constipation. I'll also provide pictures just in case.

I wanted to create that post a couple of days ago but as I already created multiple threads and I'm a new user, I didn't want to spam the forum on ring the alarm bell "for nothing". I'm writing this in case there is something obvious that I missed because of my lack of experience and gather your thoughts. So far this community has been great giving good insights, tips and comments and I really appreciate it.

I'll upload pics tomorrow, they move way too fast for my phone to take a picture that isn't blury and the aquarium light is off. Pics on the fourth post bellow, they move too fast for me to take a good picture with my phone.

Tank
What is the water volume of the tank? 55 gallon
How long has the tank been running? 3 years
Does it have a filter? Yes, Hydor
Does it have a heater? Yes, Eheim
What is the water temperature? 25°C/77°F
What is the entire stocking of this tank?
- 2x Peppered Corydoras
- 4x Kuhli Loaches

Maintenance
How often do you change the water?

I wasn't able to maintain the tank as much as I would've liked. 1x month

How much of the water do you change? 30% or top off
What do you use to treat your water? Seachem Prime
Do you vacuum the substrate or just the water? Mostly water, top of sand from time to time

On May 3th my filter broke/leaked. I added an air pump. On May 4th I installed an AC 50 as a temporary filter.
On May 5th or so I removed algae, removed almost dead plants, algae-covered driftwood, did a 90% water change. Installed a Tidal 75 running @ 50% flow, added Seachem Prime, Aquavitro Seed and Continuum defense f to the water.

I've been keeping a journal since - see bottom of the post.


*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water? Nutrafin
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.
Ammonia: 0
Nitrite: 0
Nitrate: 5-15
pH: ~7.6

Feeding
How often do you feed your fish? Once a day
How much do you feed your fish? Hikari Pellets and sometimes Omega One Shrimp Pellet before May 5th.

This is what I saw the Kuhli ate as they are quick to steal the meal of other fish from time to time:

May 5th: Bug Bites
May 6th: Bloodworms / Algae wafers
May 7th: Spiriluna Brime Shrimps
May 8th: Bug Bites
May 9th: A mix of bloodworms and Krill wafer
May 10th Spiriluna Brime Shrimps
May 11th: Krill Wafers but I didn't see them eat that yet - I think I saw them eat a Bug bite meant for the (new) tetra.

What brand of food do you feed your fish? Hikari / NorthFin
Do you feed frozen or freeze-dried foods? No I wasn't for the past few months, only pellets.

Illness & Symptoms
How long have you had this fish? 3 years
How long ago did you first notice these symptoms? The night before their death
In a few words, can you explain the symptoms?

On May 5th one of the Cory was acting more relaxed and reserved than usual. At the end of the day I saw him having no longer the energy to swim but touching him would wake him up. He was almost free floating (it's heartbreaking to see that) and then he would "wake up" and swim for a little. Before bed, he was worse but still alive.
On May 6th he was dead, belly up. I noticed later that day similar symptoms on the second cory and on the morning of May 7th he was also dead.

Tonight I noticed my Kuhli have some red path on the stomach, and 2 of them maybe are bigger in height (from stomach to back if that make sense, looking more rectangular). They are all glass surfing and look way more happy every since I added some tetra in there as they now swim during the day - before they were more nocturnal.


Have you started any treatment for the illness?
Added 2 Tbps of salt (in a 55 gallon) on
Was your fish physically ill or injured upon purchase? No
How has its behavior and appearance changed, if at all?


Since I have a very bad memory I try to keep as much note as possible:

Historique de dosage
Jour	Heure	Produit	Qte
2021-05-05	19:00	Seachem Prime	5ml
	19:00	Aquavitro Seed	25ml
	19:00	Continuum defense f	30ml
2021-05-06	11:00	Aquavitro Seed	15ml
	13:00	Seachem Flourish	4ml
2021-05-07	13:00	Aquavitro Seed	15ml
2021-05-08	10:00	Water change	8 gal
	10:15	Aquavitro Seed	15ml
	15:54	Salt	2 Tbsp
2021-05-09	12:00	Aquavitro Seed	15ml
2021-05-10	12:00	Aquavitro Seed	15ml
	12:00	Seachem co2 thing	27.5ml
2021-05-11	16:00	Water change	4.5 gal
	16:10	Aquavitro Seed	15ml
	16:10	Continuum defense f	5ml

Water tests history
		NH3/4	NO2	CO2	NO3	K	PO4	Ca	Mg	Fe	dGH	dKH
2021-05-07	14:10	0	0	-	5	-	-	-	-	-	~	3
2021-05-09	10:20	0	0	-	5-10	-	-	-	-	-	-	-
2021-05-11	19:00	0	0	-	5	-	-	-	-	-	-	-

Species	Adoption date	Sexe	Note	Name	Décès
Peppered Corydoras	2017-06-05		2017? 2016?		2021-05-06
Peppered Corydoras	2017-06-05		2017? 2016?		2021-05-07
Kuhli Loach – Black	2017-06-05		2017? 2016?
Kuhli Loach – Black	2017-06-05		2017? 2016?
Kuhli Loach – Black	2017-06-05		2017? 2016?
Kuhli Loach – Black	2017-06-05		2017? 2016?
Pea Puffer	2021-05-05	F		Betty
Pea Puffer	2021-05-05	F		Dot
Black Phantom Tetra	2021-05-05	M
Black Phantom Tetra	2021-05-05	M
Black Phantom Tetra	2021-05-05	M
Black Phantom Tetra	2021-05-05	F
Black Phantom Tetra	2021-05-05	F
Black Phantom Tetra	2021-05-05	F
Otocinclus Catfish	2021-05-05
Otocinclus Catfish	2021-05-05
Otocinclus Catfish	2021-05-05
Otocinclus Catfish	2021-05-05
Otocinclus Catfish	2021-05-05
Otocinclus Catfish	2021-05-05

Date	Heure	Notes
2021-05-09	12:30:00	Some Oto are eating on the Zucchini for the first time!
		Saw an Oto make a small brown poop
		Kuhli are hidden in the driftwood they love so much. Glad I added it back after I boiled it.
2021-05-10		Pea Puffers are frozen bloodworms from my tweezers!
		Added a coconut shell with some Repashy on it for the Oto
	PM	Saw an Oto make a small brown poop, again. I think I saw a tetra do the same
2021-05-11	AM	Except for some snails, the gel looks untouched by the Oto, but half of them look quite fat and the other half doesn’t look skinish. All seems active.
	AM	The Murder Peas ate 3 worms each this morning, yay!
		Of course the Tetra HAD to steal some bloodworms right in the face of a Pea. He looked angry.
	PM	Afraid that the Oto had too big of a belly, I looked on the internet. The lil’ thing near the tail is the sex organ of the male, not a stupid “fish lice”. Ahhh forum, I almost had a heart attack.
	EVE	Hmm, the Kuhlis, although very active, seems to have a big belly. At least two of them have some redness on the belly too. Gills look pink/red-ish a little too. One of the Kuhli seems to have a brown line near the end of the body, belly side. Take pics tomorrow if that's even possible.

I have no medicine on hand, only aquarium salt. I am already planning on buying some just in case but I'm in the research phase as there is a big list of products availble (Seachem, Api... ahhhhh) and I'm not sure which one to get. Some are verryyy expensive.

 

I know your readings don't indicate it, but my initial thought is that by replacing the filter and doing a major cleaning basically at the same time you eradicated almost all of your beneficial bacteria colony, so your nitrogen cycle has to start all over from scratch. Maybe they died from ammonia poisoning?

 

Since you said you haven't really been on top of water changes and then did a massive one I have to think what is happening has been caused by the sudden drastic change in parameters without acclimation.

Without regular large water changes things we don't normally test for build up in the tank. It happens gradually so the fish slowly get used to it. By changing out 90% of the water while also cleaning the tank the parameters in the tank changed drastically.

I do hate to say this but I fear more fish will die. I am not sure there is anything that can be done about it other than hope the losses end soon. All you can do at this point is just learn from it and try to teach others what you've learned the hard way.

Keep an eye on the ammonia/nitrite level and keep both as low as possible with water changes until the tank stabilizes. I read up a bit on the Continuum defense f you are adding. If it were me I would stop adding this product. Continue using Prime when doing your water changes.

 

I know your readings don't indicate it, but my initial thought is that by replacing the filter and doing a major cleaning basically at the same time you eradicated almost all of your beneficial bacteria colony, so your nitrogen cycle has to start all over from scratch. Maybe they died from ammonia poisoning?

Thanks for your reply. I used the same media in the new filter and the cleaning didn't involve huge scrubbing. Although the driftwood and algea must have contained some bacteria and ammonia poisoning could make sense I really don't see how. I remember on the 5th (not written down, I forget..) I had some ammonia but I filled a 5 gallon bucket and waiting a bit and my next test was clear. Maybe I just missed the spike as it could have happen between tests idk

As a preventive measure I did a "new tank protocol" with AquaVitro Seed anyway to not take too much chances.

Since you said you haven't really been on top of water changes and then did a massive one I have to think what is happening has been caused by the sudden drastic change in parameters without acclimation.

Without regular large water changes things we don't normally test for build up in the tank. It happens gradually so the fish slowly get used to it. By changing out 90% of the water while also cleaning the tank the parameters in the tank changed drastically.

Do you mean like GH, PO4, and other minerals, etc for example? I didn't think about that at all.

I do hate to say this but I fear more fish will die. I am not sure there is anything that can be done about it other than hope the losses end soon. All you can do at this point is just learn from it and try to teach others what you've learned the hard way.

The good side of this is that it's not virus/bacteria/parasite. I was very afraid there was something in the sand I could've disturbed or something... The bad thing is the Kuhli are suffering because of a mistake I made. I read some way to humanly kill a fish, but sadly most chemicals suggested isn't available in Canada and I can't resign myself to kill a fish bare hand (anyway they are so small and energetic I would probably drop them!).

Is there a change that the bloating will go away? That they will survive (and thrive after that) Or it's not a phase thing they just need to get through?
Is there something I can do to help them with the pain?
Will this affect the other new fish?

Keep an eye on the ammonia/nitrite level and keep both as low as possible with water changes until the tank stabilizes. I read up a bit on the Continuum defense f you are adding. If it were me I would stop adding this product. Continue using Prime when doing your water changes.

Yes, thank you. I bought Aquavitro Alpha which is suppose to be more concentrate than Prime, I'll see how I like it, but I was used to Prime, I should've keep using Prime indeed. It's the same company - and the same smell - so my guess is it's just a concentrate.

I must admit before buying this I never heard of the brand even. I tend to stick to what I know. But as I bought some new fish (the first non bottom feeder in 6 years haha) I wanted to make their transition smoother, so my LFS suggested that. May I ask what you don't like about this product and which one you use to help stress in fish?

I am having a hard time taking a picture of them so I took a hundred and choose the 2 that weren't the most blurry... Hopefully you'll be able to see the bloat but the belly redness doesn't show at all.




(I know, don't look at the silicon, I'm getting a new tank later this year)

 

Do you mean like GH, PO4, and other minerals, etc for example? I didn't think about that at all.

I don't really know what these things consist of. I actually highly recommend any one in this hobby buy a TDS (Total Dissolved Solids) meter. It isn't going to tell you what is building up in the tank but will show that something is. There are minerals in our tap water. Some get used, some don't. The ones that don't just keep building up if we don't do regular water changes to keep them down.

The good side of this is that it's not virus/bacteria/parasite. I was very afraid there was something in the sand I could've disturbed or something... The bad thing is the Kuhli are suffering because of a mistake I made. I read some way to humanly kill a fish, but sadly most chemicals suggested isn't available in Canada and I can't resign myself to kill a fish bare hand (anyway they are so small and energetic I would probably drop them!).

I can't be 100% positive it isn't some kind of virus/bacteria/parasite but I do think the big water change is at the bottom of what's happening. The drastic change in parameters was just more than they could handle.

Is there a change that the bloating will go away? That they will survive (and thrive after that) Or it's not a phase thing they just need to get through?

Almost anything is possible but I have to be perfectly honest and say I really don't know. Only time will answer that question.

Is there something I can do to help them with the pain?

Just make sure there is little to no ammonia in the tank. Other than that I am not sure there is anything you can do in this case.

Will this affect the other new fish?

Thankfully no, it shouldn't affect the new fish you add as long as you acclimate them. It wasn't actually the water that caused this. It was the drastic change in the parameters the fish had gotten used to.

Yes, thank you. I bought Aquavitro Alpha which is suppose to be more concentrate than Prime, I'll see how I like it, but I was used to Prime, I should've keep using Prime indeed. It's the same company - and the same smell - so my guess is it's just a concentrate.

From what I've read this product is more for saltwater tanks but I see it can also be used in freshwater so may be alright. If you still have it I will recommend you stick to Prime.

I must admit before buying this I never heard of the brand even. I tend to stick to what I know. But as I bought some new fish (the first non bottom feeder in 6 years haha) I wanted to make their transition smoother, so my LFS suggested that. May I ask what you don't like about this product and which one you use to help stress in fish?

It may just be me but I shy away from anything that claims to de-stress and add to a fishes slime coat. For the most part fish can control that just fine themselves and to de-stress them it is best to lower or turn off the light. Give them some quiet time to calm down.

My problem with any products like this is do they actually do anything other than lower the amount in our bank account and most of the time the product isn't needed. In my humble opinion the fewer things we add to our tanks the better it is for our water pets.

I am having a hard time taking a picture of them so I took a hundred and choose the 2 that weren't the most blurry... Hopefully you'll be able to see the bloat but the belly redness doesn't show at all.

It is very difficult to see what you are seeing. Sadly right now it is just a waiting game to see what is going to happen. I can only hope you don't lose any more but wanted to prepare you for the possibility that more will be lost. .

 

Oh wow I remember your tank. I am shocked this happened, your tank was looking good last time I remember

The best thing that you could have done was...do nothing. I remember you were buying a lot of fish food and I warned against overfeeding. Since you recently added fish, the cycle needed some time to catch up to the increased bioload. From your description it seems like some ammonia burns which was probably caused by the cycle being overloaded.

90% water change is too extreme, don't use salt and don't use medication. Just do nothing (and feed nothing) and let the cycle catch up.

 

90% water change is too extreme, don't use salt and don't use medication. Just do nothing (and feed nothing) and let the cycle catch up.

I kind of knew, but I had to move the furniture on which the aquarium is on for the new filter and also to put a few more inches between the aquarium and the door next to it.. :/ I'll let do it's thing, cloudiness is almost gone. Still testing params and watching closely.

I remember you were buying a lot of fish food and I warned against overfeeding.

All tests still return 0 in my small defense . And I did vacuum the sand to remove excess food. But I get your point.

Thanks for stopping by Cherryshrimp420 I appreciate it <3

 

I kind of knew, but I had to move the furniture on which the aquarium is on for the new filter and also to put a few more inches between the aquarium and the door next to it.. :/ I'll let do it's thing, cloudiness is almost gone. Still testing params and watching closely.



All tests still return 0 in my small defense . And I did vacuum the sand to remove excess food. But I get your point.

Thanks for stopping by Cherryshrimp420 I appreciate it <3

The ammonia/nitrite/nitrate is only a small part of the picture. They're indicators of nitrifying bacteria activity....but there are many more types of bacteria in a tank. When food is added, it goes to feed all sorts of bacteria and microorganisms. They can then cause weird growth on fish and lead to disease. The cloudiness in the water is an example of this non-nitrifying bacteria growth (theyre feeding on suspended food particles in the water).