Does anyone have any idea what this is??

[TheChunkyFish]

I’ve been struggling with whatever this is since October of last year. I’ve made a few posts about it, but I’m going to post one more time to see if anyone knows what this is.
I recently have been talking with another aquarium forum and they said it’s my gh and kh value, but I don’t think that’s what it is, that’s probably what caused the disease but I don’t think it’s what is happening. 
My kh and gh value used to be zero, and now the dgh is 4 and dkh is 2. Which is better than having nothing like before, still low I know, but better. The thing is if it was my kh and gh values that were the problem I think I would’ve seen improvement in my fish. 
My water parameters are 0 ammonia, 0 nitrite, 0 nitrate. 0 nitrate has always been that way for me, not sure how to raise it because when I feed the tank nothing happens to it. Idk I’m pretty confident my tank is cycled, cause these parameters have stayed the same since I’ve had this tank, if anyone knows what’s that is all about I would love to know. But I don’t think that’s the problem. However, I haven’t tested my water parameters in about a week, but they are normally consistent. I can recheck that tomorrow after I wake up. 
The only “symptoms” of this mystery disease is the fish becomes pale, like the gill area is no longer is sparkly and green, and the fins are clamped, and slowly over time the fish can’t swim very good. He lays very flat on the ground and swims like a hill stream loach, in small bursts of energy not constant fluidly moving. I could make a gif of a video if you all want to watch the way he swims. I’m not sure he will live much longer but this disease has taken one fish at a time pretty much every month. Right now I have 3 fish I started with 6. The sick fish is still motivated to eat but gets outcompeted by the other fish because it doesn’t swim well. I’ve treated both with levamisole and API general cure twice, and no improvements. I don’t have activated carbon in the filter all I have is 2 sponges, bio rings and crushed coral. I’ve also used ich-x just in case it was fungal but that didn’t really help. I feed sinking pellets but I’m guessing it’s not his diet because all the fish would be affected then.  Recently a small spot of fin rot has appeared on his tail, which makes no sense because that comes from bad water. 
The only thing I haven’t tried is bacterial medications because my tank is prone to crashing. My tank has crashed when I used bacterial meds before, so it’s probably not a super strong cycle cause from what I’ve read most healthy tanks can withstand the meds. Ill do it if that’s what everybody thinks I should do.
I’ll attach a photo but I really want to know how to help my fish and know if I can prevent the other two cories from getting this. It’s really sad watching the fish degrade. I think I’m still technically a beginner so please help me out anyone who knows what is happening. 
p.s. I know the algae is bad, I clean the water but not the algae all the time. 
 

[Tony s]

Kh and gh are the two common values of water hardness. Gh is your general hardness, the amount of dissolved calcium and magnesium. Kh is your carbonic hardness. It measures the level of carbonate in the water. Kh is related to your gh because a lot of the value of the gh is calcium carbonate. Not all. So gh is always higher. Kh is a buffering solution for the water. It prevents large swings in your water ph. Which is bad for your fish. Neither of those numbers are lethal nor do they cause diseases. So you have something else going on.

the real question is what levels of ammonia and nitrites are you testing at because those are very toxic. Or are you testing for them at all. Your symptoms sound a lot like ammonia poisoning. 0 ammonia, 0nitrite 0 nitrates would be what my local fish store calls sterile water. From the looks of the brown algae on that tank, this is a fairly new tank? Are you sure it’s cycled. If so, you should be seeing some nitrate values other than 0. Nitrates are the end product of a cycled tank. With fish in, they should be higher than 0. 
 

the brown algae in the corner is perfectly normal for a new tank. It’s not good or bad, just a bit unsightly. Green algae is actually good for your fish. It helps oxygenate the water. It helps lower your ammonia, nitrites, and nitrates. And it serves as food for some fish. The only problem it causes is it tends to form on the glass constantly, making it harder to see the fish. That said, some forms of algae are harder to remove than others. Depending on how they grow (the physical appearance). I actually like to see algae on some of the hardscape. It tells you that you have a functioning ecosystem.

 

my thoughts are that the tank is not really cycled yet. Or you’ve had enough meds through the tank, it’s killed off your benificial bacteria. You may need to restart your cycle. I would be curious what your test readings are on a new batch of tests.

ich-x and levimasole are both anti parasitic meds. Fin rot needs an anti bacterial med. erythromycin from one of the big box stores could work, following the directions very carefully. Better would be Maracyn 2 from a local fish store. 

I’m curious as to what brand of bacteria you added when you first started your tank. And how soon after you started did you add your fish. Also curious as to what type of water tests you’re using.

[TOtrees]

tough situation. what is the substrate in your photo? it looks sparkly white, and I can't imagine a scenario where you have algae on the glass (which isn't bad), and pearly white substrate. 

Also, is your tap water (that I assume you use for water changes) treated with a water softener? 

[Colu]

Your water parameters look fine What are you feeding and how often do you use a water dechlorinator like prime when doing water changes any flashing loss of appetite do you have live or plastic plants @TheChunkyFish

Edited February 8 by Colu

[TheChunkyFish]

The thing with the algae is I’ve had it since I’ve had the tank, I got this tank last summer and it was cycled around August when I added fish. My room is really sunny and so that’s why I’m assuming I have so much algae. I don’t know what you mean by what kind of ammonia I’m testing? I use the API water test kit, and those are what my readings say. I’ve been test very frequently recently because of this problem, but December 12 I tested my water and my nitrates nitrites and ammonia had all spiked high, the ammonia was .5 but everything else was super high. (I know .5 ppm is still bad) I’ve never really seen nitrates on my readings before that and now it’s back down to zero. which I made a post about earlier, but I had this mystery disease before the spike in parameters. I got these fish from a friend which probably got them from a fish store. I can ask where she got them from that would probably be helpful but yeah my tank doesn’t have ammonia as far as I can tell. I’m sure there is something up with my cycle cause I’ve had it crash a few times while having the tank. I used API quick start initially to start the cycle and in December when my cycle crashed I used Prime and Stability to cycle it and that seemed to work great. Since I know my cycle is probably weak I’m trying to avoid bacterial infection meds because I’m afraid it will crash my cycle and I’m just doing small partial water changes to see if that will help the small bit of fin rot.

The substrate is just white sand from petco. I’m pretty sure it has phosphate in it so that encourages the brown algae that could be why I have so much too and I have never been able to get rid of it. But I don’t think my algae or substrate is the problem here. As far as I know my water is just really really soft here and I don’t have a water softener. 
 

I am feeding hakari sinking pellets like 3/4 of a pellet every night, one little 4th for each fish as I’m trying to get the active healthy fish to stay away from the sick little guy so he can eat his food in peace, but I don’t think that’s the problem either. I have an api water conditioner and prime but I haven’t been using prime as I thought my aquarium was cycled. No loss of appetite, my sick fish is still motivated to eat but struggles to swim so has a hard time eating. Yes last week I saw one of the healthy fish flash once but I haven’t seen flashing this week. I have a majority fake plants other than some anubias. I did buy floating plants recently which I made a post about but they have a weird pink fuzz on them that I’m trying to get rid of before I put them in the tank. I have no idea what the pink fuzz is but it’s taking over my plants and honestly I can’t get a break from this hobby. I just want a nice healthy tank :’)

[Tony s]

I agree with colu. Parameters look fine. I would like to see nitrates. What concerns me is you say it’s constantly crashing. That’s not normal in a fully cycled tank. Most tanks have a level of resilience where they’re relatively stable. Your gh kh look fine. On the very soft end, but fine.

[TheChunkyFish]

Not constantly but I’ve had this tank running since last summer and it’s probably crashed 4 times. Which yeah is still a lot but I’m not sure how to fix that. I was planning on getting some plants and wood from a friend and that will probably have some beneficial bacteria to help my cycle. 
This could possibly be the cause of this mystery disease but I don’t think it’s what it is how bout you? 
After improving my gh and kh my fish seems to be degrading slower so that’s good I guess.

[Tony s]

The brown algae is caused the silicates in the water. It usually goes away after a bit of time. 

[Tony s]

And you’re not showing any nitrites or ammonia. Upon regular testing? Your softer water kh can allow ph to swing. But it’s not zero. So that shouldn’t be an issue unless you’re producing acids. Your clean substrate says you’re not. How are you keeping the brown algae off of your rocks or does it just not grow there. Brown algae usually covers everything. I’ve had it run rampant before. Had black sand with tons of silicates. Covered everything with 1/4 inch. 
 

did you use a source of bottled beneficial bacteria?
 

I’m just thinking out loud here. It is kind of puzzling. 

[TheChunkyFish]

Yes I think it’s weird too. I did use a bottle bacteria at first which I realize doesn’t always work I know, but yeah the brown algae doesn’t really grow on the sand… it definitely covers everything else though. And I have green algae in the sand along the glass in the side that gets the most sun but no brown algae.

How would my tank be producing acids? Just curious. 
But yeah I’m not sure what’s wrong with my fish, just that they die eventually and there isn’t really symptoms. And it’s only one at a time. It could be some mystery water parameter? Or maybe a bacterial internal infection? 
I could ask a friend if they have spare filter media, but I’m worried it will somehow come with a disease that I don’t want in the tank. 
 

Edited February 8 by TheChunkyFish

[Tony s]

Acids are usually formed by the breakdown of organic compounds. Your clean gravel says that’s not an issue. Green algae is a great sign. For the moment, to save your fish, I would go ahead and treat with Maracyn2 if you can get it. Worry about them first. Follow directions carefully. It should be available at your local fish store. I’d grab some Fritzzyme7 or Seachem stability while there. Then when treatment is over, add bacteria back in just to be safe. The bacteria can be added every few days for a bit, it won’t hurt the fish. Hopefully treatment doesn’t cause a crash, more bacteria will help. 
 

you do use a dechlorinator after every water change? I am assuming you do. Standard practice, but you never know.

have you ever tested your tap water. May be something in it. Very possibly ammonia or nitrates. I have well water, the iron is too high for me to use it without reverse osmosis. Got to be something causing your higher levels of crashing. You should be mostly stable. 

[TheChunkyFish]

I’ve heard you can take out your filter media and put it into a bucket with a air stone and it will survive, should I do that in attempt to save my beneficial bacteria? 
And I can buy fritzzyme I already have stability. And yes I do use a water conditioner, I have prime and api water conditioner.  I normally use api water conditioner. 
I have tested my tap water I’ve tested my sink water but the thought occurred to me that I use the tub to fill up the water, so maybe the water is different from the tub? I’m going to check after school but I’m assuming it’s the same. 

[Tony s]

I assume so.

You could take out the media. It's more important to take out the carbon. Carbon can grab ahold of your meds and make them less effective, or not at all effective. 

[TheChunkyFish]

I don’t have any carbon in just 2 sponges, crushed coral and bio rings. 
ok I’ll try it out and see how It goes hopefully something starts working. 🥲

[Tony s]

your bio rings may be a bit of overkill. your sponge filters should hold enough of the beneficial bacteria. No harm, but not necessary. 

[TheChunkyFish]

Ugh my tank totally crashed. I have 1.0 ppm ammonia today. I’m gonna do like a 50% water change I think, and ask a friend if they have spare filter media because I am so done with my tank crashing.
my dgh is 6 and dkh is 3 though. 
 

[anewbie]

Your gh and kh match mine; never had a tank 'crash' though i think something else is happening. Also 1.0 ppm would kill those cory in a day. I never use carbon - consider the stuff a waste. Most of my aquariums just have sponges though I dont' see mention of the size; the limit of sponges is creating enough current for larger aquariums to provide adequate filtration. 

[TheChunkyFish]

I don’t have carbon and I’ll been using seachem prime and stability I’ll watch it see what happens.