Kuhli loach deaths

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Aquarium Advice Newbie
May 6, 2023
I've lurked old threads on this forum and a number of other sites over this issue before, but it's happening a third time and I need to outline it to more experienced people to feel like I'm even a little bit sure there is nothing I could try.

The overgeneralization is, I have tried to get together something of a recommended kuhli loach group and have had two die in a specific feeling pattern, and a third following the trend as of late.

There is another one death that's an outlier only in that he died in two days, after I was warned he looked small and sickly by the LFS who didn't even want me to buy him the first time I tried. To be fair she kind of also thought that about one of the two pattern deaths as well.

Those two looked essentially like: Fine 1-2 weeks, tail clamped 1-2 weeks, and die after just over a month of them being in the tank. So the third today has just reached his tail clamp being noticeable the past week or two and now I worry every time I see he's out of hiding spots more kind of just, less reactive to the lights coming on (which I've killed for the day because of it) and a little more listless seeming. He however, is quite close to two months in the tank and I had zero concern for him the first full month.

And yet my VERY first kuhli, in the tank with that outlier first death, when I was an idiot and my tank wasn't even cycled (I ended up on the fish-in cycle by accident but feel it ended up okay that route), is alive and well. He has never showed any of these signs and is the only one to make it to a bigger size (being a minimum 8 months old now). There are also two java loach who have never looked affected in any manner, and a female betta who is also healthy throughout the timeline. I even thought she could be a problem but she sometimes bothers their omega pellets more than she pays any mind to the loaches.

10 gallon tank started 8 months ago, so some iterations during the deaths but currently:
-Planted, although I wouldn't call it heavily, I have some more in quarantine to fill it even more
-I had dosed seachem flourish occasionally, but have enough algae to say I don't need it and never noticed a correlation in timings
-Airstone added after two total deaths
-HOB the whole time with a special buffer
-Heater 78f
-PVC pipes, ceramic cave, ohko stone, spiderwood piece
-Went from a white sand with river rocks, to flourite red sand (which is disappointingly just a small gravel) with the same river rocks. I note this because of thinking they would feel more comfortable blending, and I believe it did, but I hated the trade off of less soft for scavenging just because flourites name labeling is messed up - their black sand is amazing :(
-Omega one catfish (used to be shrimp I guess) pellets is their main, plus if they get some fluval bug bites from the betta, occasionally frozen spirulina brine shrimp goes in, and only very very recently I am trying out repashy community once or twice

-Ammonia 0
-Nitrite 0
-Nitrate 10-20 (there's nearly a 10ppm base in my tap which is annoying)
-I do weekly water changes, shoot for 30% lately because I felt like maybe I was doing too large in the past

-pH like 7.6 to 7.8, I always have a weird time reading this one, but the internet has made me feel like with the amount of time things are stable in between this is an unlikely cause, similar to if there was ever an ammonia spike I didn't catch like more than just ONE loach would be showing issues

Once learning that there's a high chance these are wild caught, I mostly concluded that HAS to be it. With the amount of effort I put into tracking params, appropriate water changes, and the other fish being just fine the whole while, I don't know that I could be doing anything differently. But I don't like that answer if I have this third one pass, so here I am for some healthy dialogue.

Thank you for hearing me out
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A couple of things missing in your description: GH ( Hardness) is going to be important since wild Khulis come from extremely soft water with a much lower Ph than yours. ( Should be closer to neutral to slightly acidic: 6.0-6.5/ 7.0)

Water movement: is there any at the bottom of the tank? they like flowing water.

How often do you feed the fish? They should be fed multiple times a day( or nighttime since they are mainly nocturnal fish). High protein foods are a must with the brine shrimp daily to help with digestion and keeping their " system" flowing.

There's some debate on minimum tank size since they are a small fish but a 30" long tank seems to be the most often suggested minimum size which means your 10 gal is too small for these fish anyway.

Have you ever tested the water just above the substrate level? Some of the attributes of plant soils will have ammonia or ammonium levels higher closer to the bottom of the tank and if there is little water movement, that can be a disaster for bottom fish. Considering your Ph is above 7.0, ammonium will convert to toxic ammonia. It may not be high enough to outright kill the fish but enough to make them sickly over time.

Do you quarantine your new stock when you get it? Bottom fish species have a history of having internal parasites or worms that could explain why the deaths are over a period of time and not instant. Do you treat new Khulis for these?
Hi and welcome to the forum :)

A picture tells a thousand words. Any chance of pictures of the fish and one of the entire tank?

How often and how do you clean the filter?
What is the special buffer in the filter?
What filter media are in the filter?

Do you gravel clean the substrate when you do a water change?
Do you dechlorinate the new water before adding it to the aquarium?
Do you have specific buckets and hoses for the aquariums or do you use any bucket around the house?
He was gone when I got up today, so, my gut was correct there...

I don't recall the exact hardness, but I do know at the beginning I had the dipstrips instead of the API kit, and established that GH was quite high; that with the pH did linger as a worry.

Water at the bottom of the tank: only as low as the airstone goes not anything horizontal. The HOB flow drops straight down but I actually have a soapdish/sponge buffer, maybe that should go away?

I feed a broken pellet in the morning now because one of the javas tends to check stuff out in the day; at night I drop 2-3 broken pellets depending on how well that one disappeared. The pellets are 42.29% protein.
Are you saying I should be doing the brine shrimp daily or thought that I am? It's definitely a lower protein on the package, I don't give it regularly.

I had hope to get them into a 20 long down the line once I learned of that debate, but 30 long actually sounds like news to me so thank you for pointing that out. Seriously good info you guys provide here. Still makes me feel a bit like I have a ways to go in this hobby, but I think my kuhli run is over. I hate having just three but there's no point in killing more fish. My poor original stripe has literally seen four friends go, now.

I'll do some testing just above the substrate moving forward. The flourite sand is inert substrate, as I understand it, I'm kind of weird for a "planted tank." I did forgot to mention having 1-2 root tabs in there, though. I had never considered it could read different areas so that is good info. It would really make you're point stand with these all being gradual deaths :(

The short answer is no, I didn't quarantine in the beginning of all this. I have a bad habit of making excuses so I won't. And I do now, but that's a too little too late thing. Even when I was going to for the last set of three loaches, I was only going to do two weeks and now have a believe in a firm four for anything.


I can work on some pictures (I have plenty, it's getting them loaded up).

I clean the pre-filter fairly often once the spiderwood was added only because it cakes.
I never do that the same time as the "internal" HOB sponges, and I only do those if the flow looks low (ie caked). I know those house the most important stuff.

The buffer is a (never used) plastic soap dish suctioned with same sponge type over half the holes to leave some motion.

The sponges are just like black semi-coarse aquarium ones? Never used original media.

I do gravel vac.
I used an Aqueon dechlorinator when I first started and use Prime now.
I bought new buckets and hoses at the beginning of this.
I did, come to think of it, acquire some used one's from my sisters old tank, that was after two total deaths but still could be worth some questioning for me to do.

Thank you guys again for hearing me out.
For fish with small mouths, I'm not a fan of pelleted foods. Better to feed frozen or flake for them IMO. Khuli loaches need meat so foods like black worms, bloodworms, shrimps and flake foods are good choices for some of the meals but you want to add the infused brine shrimp as one of the feedings every day not for the protein value but for the vegetable matter inside them and the chiton in their shells to help with intestinal " flow". Too much protein causes constipation so you need vegetable matter to help them poo. Fish really need a varied diet. Fish keepers get lazy sometimes and find one food or 2 foods and just feed them those. That's how fish get sick because no one food carries all the nutritional needs of the fish. ( Just as no one food we humans eat has everything we need. ) In my Hatcheries, I fed a lot of live worms and high protein flakes for conditioning the fish to spawn so that was a lot of protein. I used the brine shrimp ( live or frozen, never freezed dried) as their last meal of the day so that it had all night to work on pushing out that protein. Since my tanks were all bare bottoms, I could see the results and the results were a lot of poo in the mornings. ;)
As for quarantining, unfortunately, with today's fish, so many come from farms that have....let's say questionable practices when it comes to using medications, so it's possible that once the fish are no longer in the presence of those medicines, they break down. This is why today more than ever before, quarantining is highly recommended. As for how long to QT, the longer the better. Bacterial and fungal issues usually show up within the first week +/- but parasites ( internal and external) don't always show up that fast. There are parasites with 90-100 day life cycles. Thankfully the longer ones are more rare in freshwater but they do exist. A good quarantine tank is just a miniature version of the main tank so the fish should be able to live in it for months. Once they have passed that stage, then they can go into the main tank. ( and just an FYI, medicating is not always done in a quarantine tank as many medicines will effect the bacteria bed that is keeping your tank stable. Medicating is best done in a bare bottom tank with a measured amount of water so that the medications can be properly administered. ) So it's QT for observation, acclimation and recovery, Hospital tank for medicating. (y)
Okay, so frozen brine shrimp are now being better incorporated (and the repashy). I was crushing the pellets up in the past but the seemed to soften okay without. I'll still assess those better with working out the new regime.

I think I found an image host that will work here so let's see if this works:


(Hades is out knowing some water change is about to happen)

I was going to be adding plants coming out of quarantine today, and did a pH check again because it's been lurking in my mind.
It actually comes out of my tap 7.2-7.4 (I know still high for them), but in both my 5 and 10 gallon reading 7.6-7.8, possibly even 8.0 on the high test.
I knew I was confused in the past but the internet of course convinced me the loaches would "adapt" and since my very first one has somehow done so, I bought into that.

But ever since you pointed it out it's been weighing on me as the biggest potential cause (with the GH in combo). I just can't figure out what's raising it? Now I'm hung up on the internet being conflicting again about it being possible the plants are doing it? Over this whole chronology I have kept making changes for thinking more plants = better, and today's are for better low ground cover.

Literally these two links are on top of each other, like others:
"Plants are highly effective at naturally lowering and maintaining pH levels. Plants such as peat moss, driftwood, and almond leaves efficiently reduce pH levels ..."

"Plants can increase the pH level of water in the aquarium as they reduce carbon dioxide..."

Again, I know my tap isn't right for them either, but if I made it even worse, that's what would be great to solve.
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