[Scutler]

Hello,

I've been having an issue for a long time (over a year!), with my 90 gallon low tech tank. For whatever reason, fish just won't stay alive and I have no idea why. My pH is about 7.4, temp about 79-80 degrees, ammonia is 0, nitrite is 0, nitrate 10-15 ppm, kH about 4 degrees, unsure of gH at the moment as a new test kit is coming in the mail shortly. I have tried tetras, rams, bristlenose, as well as a few others but nothing except cories last more than a few days and even they only last a few weeks at best. I do however have a large colony of Malaysian trumpet snails and 2 nerite snails that have been in there since the beginning (about a year). I leave the light on around 6 hours a day and have a Fluval FX6 for filtration. I've tried restarting the tank 3 times now and letting it cycle for multiple weeks each time but to no avail. The tank is currently planted with a variety of species that are growing fine. I have no clue what could be wrong.

Any help with this issue would be greatly appreciated! If any more details are needed feel free to ask.

 

[Blue Ridge Reef]

Are all fish coming from the same store? Any signs of illness before the fish pass? Do they eat and behave normally and just die out of the blue? Most diseases should be gone by the time the tank has run fallow for 60ish days. I'd suspect poisoning but you'd think nerites would perish if hardy fish are. Sometimes a photo can help show something we wouldn't even think about if you can post one of your tank. Zebra danios are about as hardy a fish as in the hobby and inexpensive. I'd try 6 or so of those from a different source and see how they do before trying more fragile stuff like rams.

 

[victorusaconte]

For tetras, rams and practically for any central or south american fosh the ph should be slightly acidic 6.5- 6.7 and kh near 0 as well as gh near 0.

The hobby most difficult part is to mimic the environment.

Throw some almond leaves or jack fruit leaves. Anything that would low ph and provide health benefits.

They don't like HIGH light and will die out of stress.

Nitrates should be 0 too.

I wish success for you. And for sure, as the comment above said, send us some pictures

Edit: soft belly fish (cory) die if the substrate is rocky and sharp.

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[Scutler]

Thanks for the responses I'll try to answer what I can.

I have tried a few different stores around me so they're not all coming from the same source. None of the fish are really active once in the tank aside from the cories, most others just hang out towards the bottom even if they make it past the first few days then die. It looked like most fish were breathing fast in the tank aside from the cories, but none were hanging out towards the top so I'm assuming it wasn't an oxygen issue, especially since I have good surface agitation thanks to the strong filter. Aside from that the only fish I noticed any symptoms on before they passed was the rams, they became bloated and like I said lethargic so I'm assuming it could possibly have been dropsy, but to my knowledge, this is usually only caused by an issue with water quality which I haven't discovered any signs of at least when it comes to testing. Also, the rams stool was a whitish clear and none of the fish would eat. I have tried zebra danios and I know they were healthy because they were from my gfs tank and she had them for over a year without any issues, they didn't last.

Yea, my goal was to have a lot of South American species in this tank, tetras, bristlenose, rams, possibly angels depending. I have an RO unit I've recently been using to slowly try to bring down pH, nitrates and hardness with small <10% water changes per day, but I've only been doing this for the last 3 or 4 days. My light isn't too bright as its a low tech tank and its only operating at about 70% output, also was planning to add a few floating plant species like duckweed to shade the tank further. The substrate is sand so I don't think that was the issue with the cories. I know rams tend to be on the more sensitive side so that was a dumb move on my part before getting a few hardier species to survive in the tank, but as I mentioned earlier in the past I've tried zebra danios and even they didn't last more than a week or two.

As of today the kH came down to 3 degrees due to the water changes but the pH is about the same.
Here's a pic from a week or two ago if you can view it.

https://imgur.com/a/H2I93Jo

 

[victorusaconte]

Thanks for the responses I'll try to answer what I can.

I have tried a few different stores around me so they're not all coming from the same source. None of the fish are really active once in the tank aside from the cories, most others just hang out towards the bottom even if they make it past the first few days then die. It looked like most fish were breathing fast in the tank aside from the cories, but none were hanging out towards the top so I'm assuming it wasn't an oxygen issue, especially since I have good surface agitation thanks to the strong filter. Aside from that the only fish I noticed any symptoms on before they passed was the rams, they became bloated and like I said lethargic so I'm assuming it could possibly have been dropsy, but to my knowledge, this is usually only caused by an issue with water quality which I haven't discovered any signs of at least when it comes to testing. Also, the rams stool was a whitish clear and none of the fish would eat. I have tried zebra danios and I know they were healthy because they were from my gfs tank and she had them for over a year without any issues, they didn't last.

Yea, my goal was to have a lot of South American species in this tank, tetras, bristlenose, rams, possibly angels depending. I have an RO unit I've recently been using to slowly try to bring down pH, nitrates and hardness with small <10% water changes per day, but I've only been doing this for the last 3 or 4 days. My light isn't too bright as its a low tech tank and its only operating at about 70% output, also was planning to add a few floating plant species like duckweed to shade the tank further. The substrate is sand so I don't think that was the issue with the cories. I know rams tend to be on the more sensitive side so that was a dumb move on my part before getting a few hardier species to survive in the tank, but as I mentioned earlier in the past I've tried zebra danios and even they didn't last more than a week or two.

As of today the kH came down to 3 degrees due to the water changes but the pH is about the same.
Here's a pic from a week or two ago if you can view it.

https://imgur.com/a/H2I93Jo

Nice tank man, that will be so cool when they grow up. Look at a video of mine here. Like i said, the almond and jack fruit leaves are super cool looking additions and healthy as well. Also looks more natural.

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[SueD]

If anyone decides to read this long post, let me first apologize for the length.
I have been suffering from insomnia for over 3 months, so I need something to do at 2:30 in the morning.

I find threads like this so frustrating to read and I really hope you can find an answer that will solve your issues. I wish I knew more but tend to be a more casual hobbyist and don't delve too far technically into things as others can to help you. I think I may just be lucky with my water parameters here, as I have kept mostly tetras, pencilfish, endlers, rasboras and cories. And some years ago had BNP's and an angel. My PH runs 7.4 - 7.5 and all of these species do very well in my particular water. I also pulled all my heaters except for one tank and my tanks usually run around 74-75F.

But just to tell a recent story of a frustration of mine. I have a 40b, a 25g, two 20g longs, and one 5g. The 25g has pencilfish, a single sterbai cory pushing 8-9 yrs, and endlers - tons of endlers. I've moved many endler males around to 2 of my 20g tanks to add some top activity there which has been great in these tanks.

I recently decided to restart my Spec V when the last rasbora aged out. New decor (dragon stone instead of the wood I usually have), new plants, substrate, filter was still cycled. I used Tahitian Moon sand for the substrate and started with 3 hastatus cories. I also added a pair of endlers (not from my stock - different species) who died very early on. Tried a 2nd pair, also not from my stock and from a different supplier. These also lasted no more than a few weeks. The hastatus, meanwhile, were doing fine. So I tried once more with 3 of my own male endlers. About a month and they were gone. What's happening?

I've read a few posts here and there about issues with Tahitian Moon sand, but I had used this years before with no issues. And the hastatus cories were doing so well. But I decided to tear this out and replaced it with Caribsea Peace River sand (really tiny gravel - love it). Added back the stone, plants, 3 hastatus, 2 more of my own male endlers and 2 aging Ruby tetras (Axelrodia riesei) from another tank. It's now almost 3 months since the change in substrate and everybody is doing so well.

So could it have been the Tahitian Moon sand? I really don't know. All of my tanks have the same water, same maintenance, no problems moving endlers to my other tanks, just this one. And now they seem to be finally surviving here. Still early, but looking good. Even those aging ruby tetras.

There's so much experience here, I hope someone is really able to better help you solve the issues with your tank. I understand the frustration all too well and wish I knew more to help you myself.

 

[Flow]

They don't like HIGH light and will die out of stress.

You repeat this ad nauseum on so many other threads. It's just not true in a reasonably well-planted tank.

 

[Asteroid]

Most important thing is clean, fresh, stable water. If fish aren’t wild no reason to adjust to natural environment from my experience. I’ve had tetras in KH 4, PH 7.5 and now I have them in KH 8-12 and PH 6.5 and no deaths in almost 1 1/2 yrs. Aim for practically no nitrates organically and dose to requires levels.

A nitrate reading of 15 organically and the same 15 dosed is completely different.

 

[Deanna]

Given the commonality of lethargy along the bottom and rapid gill movement, I’m inclined to think, first, in terms of water quality. However, perhaps we can draw @Discusluv in to work through the disease potential.

What is your water source and do you use a water softener? I’m assuming that you are treating new water if there is any concern for chlorine/chloramine. When you change your water, does the tank temperature remain relatively stable (+/- 5 oF)? Does your tank water have an odor? Has your ammonia test expired?

What are you dosing (product and quantity), in terms of ppm, and how often? What is your feeding regimen (frequency and quantity) and what are you feeding?

Substrate type and how long has it been in place? How do you clean the substrate?

What is your filter setup (media used and cleaning routine)?

Any chance of getting a TDS reading (TDS meters are cheap)?

Is the tank exposed to any environmental contaminants?

How do you acclimate new fish?

 

[PlantedRich]

Fish we buy in shops have rarely been to their native environment, so I do not think of that as killing a wide range of fish as many adapt very easily. In general it is far better to not focus too closely on the book specifics for any group unless you know they are a species known to be fussy. Keep the water stable and give them time to adapt and most do well, even in water far from ideal.
I raise and breed angelfish in totally hard alkaline water which is totally NOT what the books call for doing!
But I would look carefully at how you treat the fish when bringing them home. Do they stay in the bag long enough for ammonia to build and then they get gill damage before going in the tank?
Do you use any special soap, hand cleaner, etc. which ight be transferred to the water off your arms?
Definitely look at how you are treating your water for chlorine/chloramine!
But to start sorting the problem, I suggest doing things a bit different if you bring more fish in. Perhaps try acclimating them to your water in a different way. Instead of directly into the problem tank, would it be practical to have a large container like a bucket set up with good clean fresh water of the sort you use in your tank, put the fish in it for a long enough period for them to settle down and check how they are acting?
What I would want to do is see that I am not doing something totally wrong in buying/ moving them home or that there is something in the tank which can't be tested but is killing the fish. You've mentioned fish which tend to be nervous, twitchy and generally used to running for their life and they will be breathing hard when coming out of a bag, so I would want to give them a few hours in something like a bucket with a towel over it to let them settle and then see how they act.
If they act somewhat nervous but are swimming and acting normal, then when you put them in your tank, they become stressed sit near the bottom, you have to look closer at the tank,etc.
Any chance there is some decor that looks "so nice" but is actually a toxic waste dump? Many poisons will not show on tests we use.

 

[Deanna]

But I would look carefully at how you treat the fish when bringing them home. Do they stay in the bag long enough for ammonia to build and then they get gill damage before going in the tank?

This is a good point. I bring a small dropper bottle (from Salifert test kits), filled with Seachem's Prime, whenever I buy fish from my LFS. I add one drop to each bag of fish before they close the bag. Gills are easily and quickly burned by ammonia and a trip from the LFS longer than about 10 minutes can begin to create such problems.

 

[victorusaconte]

You repeat this ad nauseum on so many other threads. It's just not true in a reasonably well-planted tank.

I would like you to experiment by yourself and study the concept of HIGH light in an aquarium.
If it is not true, nothing to worry about then.
Wish you success


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[Scutler]

First I want to thank everyone for all of the responses! It's so reassuring to see such a big response to my post and it really gives me hope that I can finally get to the bottom of this. I'll try to respond to everyone's post in the order they were posted. It's going to be long so I appologize in advance.

Victorusaconte: Your tank video was awesome. With the almond and jack fruit leaves that'll lower both hardness and pH correct? Also how long do they continue to have this effect when added to the aquarium and do they leech tannins into the water? Side note: Apistogramma are awesome, jealous lol.

SueD: Don't worry, I read your entire post, and believe it or not you may have led me much closer to my answer than you thought. It seems like you had a very similar problem to mine and now that I think about it I'm pretty sure the black sand cap that I have in my aquarium is in fact Tahitian moon sand (at least in part). I don't remember for sure if it is because it was added about a year and a half ago, but I'm almost positive it is at least in part (no pet store had enough of any one type of black sand so I believe I may have had to mix two or three different types, one of which I believe was Tahitian moon sand). I never heard of that being an issue for anyone, but then again I never checked. I did however consider changing out my substrate the only issue with that is my colony of MTS which inhabit the sand in what I imagine to be the hundreds, and I haven't thought of a good way to change the substrate while not removing any of them.

Asteroid: I wasn't aware that 15 ppm of organic nitrate is any different from 15 ppm of added nitrates (from a product like Seachem nitrogen I'm assuming?). Currently, most of my nitrates are organic as I haven't added any, but as time goes on it is slowly coming down thanks to plants, and I often don't have any species other than the snails in there producing waste, plus not much food is being added (except for the few days when I try to add fish).

Deanna: (Sorry it's so long) When I initially filled the tank I used tap water, I live in New Jersey and the water tends to be hard with a higher pH. I add Seachem Prime whenever I add tap water. I haven't used a water softener, but as you can see in the pictures there are a few moderate size pieces of driftwood in the tank (not sure how much these pieces will affect water in a 90G tho). The past few days I have been doing small less than 10% water changes using RO water instead of tap to try to soften the water and bring down the pH some (and get out any potential toxins that may be in the tap that I can't test/neutralize), it comes out super slow so the temperature in the tank remains stable at around 79-80. There is no odor coming from the aquarium. It is possible my ammonia test may be expired, but whenever I lose fish and return them to the store I bring a water sample, and every time they tell me the same readings I get with my tests at home. The only thing I've dosed since restarting the tank two months ago was a capful of Seachem Flourish (only 2/3 the recommended dosage, not sure of the ppm, sorry) and this was only once at the beginning of September (still eyeballing what my dosage amount and frequency will be depending on plant growth). Feeding I only feed flakes when there are actually fish in the tank I use Omega One Super Color flakes ( a pinch a day), I'll put in a single pellet of Omega One shrimp pellets every other day for the snails and corys, and occasionally I'll add a half tablet of Tetra Pro Plecowafers for the snails and corys as well. For my substrate, I have eco complete underneath a black sand cap. I'll skim over the sand when doing water changes if I notice a lot of waste or leaves, but there's never really any. To my knowledge, the MTS are capable of preventing phosphate pockets from forming since they're constantly stirring up the sand. The substrate has been there for over a year. Right now in the FX6 I have the foam filter pads that sit in the outside, carbon foam pads, fine filter polishing pads, water polishing pads, and ceramic rings for biological filtration. I cleaned the filter and threw away all the old media except for the ceramic two months ago when I redid everything and replaced it with new. I haven't fallen into a cleaning regime for the filter yet as it was just redone two months ago and nothing has really been in the tank aside from snails. I actually ordered a TDS meter yesterday so I should have results soon. I can't think of any environmental effects on the tank, its in my living room and our window blinds don't allow in much light. For acclimation I'll usually float 10-15 minutes then open the bag and add about 5mL of tank water to the bags every 5 minutes for another 10-20 minutes then add fish to the tank without adding bag water, I might try drip acclimation next time using a bucket over the course of an hour or two. I really like the idea about bringing the prime to the store to add to the bags, I might do this next time I purchase fish, I feel like this is something stores should start doing as a courtesy if it makes that much of a difference.

PlantedRich: I talk about at the end of Deanna's response how I currently acclimate fish, usually takes about 30-45 min so I suppose ammonia buildup is possible. I can't think of any special product I use that could get into the tank, especially since I try not to go into it too much. I have an empty 30 gallon in my basement I can fill with tap and treat with prime to use holding tank if you think that's a good idea? The only decor I have are live plants and some manzanita driftwood. I used to have dragon stone in there but I took that out months ago and restarted the tank twice. If I used the 30 gallon as a pre tank holding tank should I let it cycle or just treat it for ammonia/ chlorine with prime and heat it to the same temp as the main tank since they'll only be in there for a few hours I'm assuming? I'm also not opposed to setting it up as a bare bottom quarantine tank to house fish for a day or two before adding them to the 90 to monitor their behavior and see how they react differently once added to the 90. Thoughts?

Overall, what are the thoughts on the small water changes replacing with RO? I know my pH and kH aren't too crazy high but at this point, I'm more concerned with something in my tap being toxic to fish that I can't detect, lower pH and hardness is just a bonus. Has anyone else had issues with Tahitian moon sand as a substrate? Seems like there's a variety of things I can try not really sure where to start.

 

[victorusaconte]

Yes
The leaves will make the water brownish yellowish, which they prefer. And dark black substrate for tetras is better cause they like dark environments.

Also, when the other dude answered me with the high light not being true, if you are wondering whats the point, he said that high light with plants its not a matter, contradicting itself. Its called "shades", proving my point and "nauseous" insistence on high light posts.

(Basically, i have to thanks him on proving my point, trying to diminished me)

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[SueD]

I really wouldn't bother with adjusting PH as I believe the fish will adapt to yours. Changing out substrate is, of course, a much larger project in a 90g than my small 5g but oh, wouldn't that be great if it solved your issue.

As I mentioned, when I first used the Tahitian Moon it was many years ago. It was easily found everywhere and I had no issues with that tank. I restarted this 5g just about a year ago and had a hard time finding this substrate. Was wondering if it was starting to be discontinued. I still wonder if that was my problem but it's the only change I've done that seems to have turned things around.

As for MTS, yuck! I have them too, everywhere, in some of my other tanks. I've spent lots of $$$ on assassins with great success over the years but these good guys don't seem to breed well enough to sustain themselves. So as they die out the MTS take hold again, rapidly. You know how easy it is to have hundreds in such a short time - why worry about them. They'll be baaaack! For now, my 5g is free and clear of any snails except my nerite as I've only used TC plants and one anubias that apparently was also clear of pests.

 

[Discusluv]

I really wouldn't bother with adjusting PH as I believe the fish will adapt to yours. Changing out substrate is, of course, a much larger project in a 90g than my small 5g but oh, wouldn't that be great if it solved your issue.

As I mentioned, when I first used the Tahitian Moon it was many years ago. It was easily found everywhere and I had no issues with that tank. I restarted this 5g just about a year ago and had a hard time finding this substrate. Was wondering if it was starting to be discontinued. I still wonder if that was my problem but it's the only change I've done that seems to have turned things around.

As for MTS, yuck! I have them too, everywhere, in some of my other tanks. I've spent lots of $$$ on assassins with great success over the years but these good guys don't seem to breed well enough to sustain themselves. So as they die out the MTS take hold again, rapidly. You know how easy it is to have hundreds in such a short time - why worry about them. They'll be baaaack! For now, my 5g is free and clear of any snails except my nerite as I've only used TC plants and one anubias that apparently was also clear of pests.

I hate MTS snails. Only had them once and they grossed me out so much I tore the tank down. The soil moved- it was vile.

 

[PlantedRich]

Before jumping to the really hard stuff of changing out the sub, I would want to be sure it was a problem. One way to begin to sort the potential problem is using the 30 as a QT but not for the normal reasons of watching for disease but to let you know that all is well with the moving bagging, adding to the tank and your water. If you get them home and they can live in the smaller tank for some amount of time, even a week, that should tell you they are okay. Then if you move a few over to the main tank, you can have an almost scientific method or experiment. you have a set of fish who may get sick while you have a "control group" who are not exposed to the main tank.
Kind of like the testing for the virus shots? Some get the real stuff while others get the placebo? How long to continue the experiment, will depend on how safe and sure you want to be that the main tank is okay.
I do not feel water PH, GH or KH are killers alone but more likely to stress fish and that stress makes them more prone to disease. Same thoughts on high light, it may be stressful but no cause of death directly. I feel we can spot severe stress and light will drive some to hide more than normal and I see it long before they die. With lots of plants, I would expect fish to be hiding in and under the plants long before reaching critical.

 

[Discusluv]

Given the commonality of lethargy along the bottom and rapid gill movement, I’m inclined to think, first, in terms of water quality. However, perhaps we can draw @Discusluv in to work through the disease potential.

What is your water source and do you use a water softener? I’m assuming that you are treating new water if there is any concern for chlorine/chloramine. When you change your water, does the tank temperature remain relatively stable (+/- 5 oF)? Does your tank water have an odor? Has your ammonia test expired?

What are you dosing (product and quantity), in terms of ppm, and how often? What is your feeding regimen (frequency and quantity) and what are you feeding?

Substrate type and how long has it been in place? How do you clean the substrate?

What is your filter setup (media used and cleaning routine)?

Any chance of getting a TDS reading (TDS meters are cheap)?

Is the tank exposed to any environmental contaminants?

How do you acclimate new fish?

I no longer do sick fish stuff. But, you are in good hands with @PlantedRich

 

[Deanna]

Make sure you are feeding enough. White poop can be a sign of insufficient feeding, but it can also be other things. They should have enough food to last about 5 minutes before being consumed.

TDS may provide a signal if there is a lot more in your water than the GH, KH and NO3 would indicate.

I don’t think that any of your GH, KH or NO3 readings are cause for concern, nor do I think that your lights are affecting the fish. This is something else.

@PlantedRich has a good idea about using the 30-gal as a QT to rule out anything in your main tank. Leave the tank bare (no substrate) and no need to cycle the tank. Instead, put a bag of Seachem Purigen in the filter and monitor ammonia daily (Seachem also makes a good sensor; “Ammonia Alert” which is useful for this).

When I acclimate new fish, I match the GH of the tank water to that of the LFS water, before adding the fish. I also verify that the TDS of the tank QT water and the LFS water are within 10% or 50ppm of each other, whichever is greatest. After observing the fish for 3 weeks in the QT, I change about 25% of the QT water, daily, with the main tank water and, after four days of this, move the fish to the main tank. I keep Seachem ParaGuard handy in case a disease appears.

Prior to moving the fish into the QT, I keep the fish in a plastic trash can (dumping the entire contents of the LFS bags into the can) and drip acclimate over a two-hour period with water from the QT.

Don’t feed the fish until the second day and it is better to not use lights the first day.

 

[SueD]

I hate MTS snails. Only had them once and they grossed me out so much I tore the tank down. The soil moved- it was vile.

My sentiments, exactly. I also tore apart one of my 20g's because of these but that's such a drastic step that I've made relative peace with them right now. They just transfer from tank to tank. It was only maybe 6 months ago that my 40b was free and clear and now they're back there as well as in my 20g's. I'll go the assassin route again when I feel like spending the money. To be really effective, I was dropping 20-25 assassins into each tank, and then some more. Why these good buggers didn't breed is beyond me. But I stopped using pellet
foods some time ago which I believe has helped some with the MTS numbers.