Nothing survives... out of ideas and about to break this tank down

[mad_tunes]

Hi,

Sorry to make my first post a plea for help, but I'm at a loss with a tank I've been trying to get going for the last few months and might be about to give up on it.

As a little backround, I've had various small tanks for years and have generally got on OK.
I had a couple of small tanks on the go, one with some pygmy corries, Kuhli loaches and red charry shrimp in it and another with some bronze corries and endler guppies. Both running pretty well for a year or two now.
Back in December I decided to step it up and aquired a second hand Aqua one Oak style 230, a 245L pretty tall tank on a cheap conti-board cabinet (https/www.aquaone.co.uk/focus.php?product_range=OakStyle Yorkshire Collection). Got it along with a Fluval 470 and reasonable but no-name LED light bar.
The plan was to start up this bigger tank and then move all the livestock from the smaller ones into it, but I haven't managed to get that far.

Forked out a fortune and put way too much reading into getting it setup.
There are mesh bags filled with lava rock at the bottom along the back, to build a little height into the back corners.
The rock was sold as Seiryu rock. The woods a mixture of Redmoor and Mopani.
Substrate's 'aquagrowth soil' by Prodibio (like this but the larger not-shrimp version)
Rigged it up with a fancy in-line heater, inkbird controller and 2nd normal glass-tube heater in the tank as a backup
Got an in-line CO2 defuser, Strideways PRO CO2 Regulator Plus and two 3.15kg CO2 bottles.

It started out like this:

...and seemed to settle down nicely.

After it'd been running and the plants had been doing well for a few weeks, I slowly added 12 pygmy corries, 4 kuhli loaches and 6 sparkling gouramis. Pretty light stocking for a tank of this size...
Things seemed fine for a few weeks, then everything started dying.

The fish have no sign of a problem that I can see, other than seeming to get shy after about a week of going in the tank and then slowly dying off over the next couple of weeks or so.
Over about month I medicated with Interpet Anti Parasite, esha 2000 and Esha Exit. More out of despiration than knowing a cause and treating it.
I've completely stopped anything-CO2, fearing I might have been over-doing it.
I had been dosing with JBL Ferropol, but stopped that a month or two ago now just to reduce the number of variables.
With no CO2 or ferts, the plants are looking quite sad compared to the first month

I've been changing somewhere around 25-30% water weekly, with the odd 50%ish after medications.
Temp was originally 24C, but I've raised that to 26C (over a week) after reading it would be better to keep off parasites like ich.

After two batches of fish, almost everything had died off so I let it run for a couple weeks hoping whatever bug might be in the tank might die off with no fish in there.
Kept feeding it to keep the cycle going, testing as usual and not seeing anything hugely wrong.
Then my filter developed a terminal leak so I forked out £200 and replaced it, moving the media from old to new.

A couple of weeks ago I put 6 more pygmy corries and 6 sparkling gouramis in again.
I'd bought them to go in this tank, but kept them in one of the small tanks for a few weeks first-they were doing fine until I moved them into the bigger tank.

I was originally testing using an API master test kit, but then realised it was getting on a bit, so got myself a JBL Combiset and a handful of test strips to have something to sanity-check things against. So I have two batches of test results with slighlty different sets of tests in each:

Sorry to make it such a long plea, but with nothing I put in it lasting longer than a couple of weeks, after so much effort, I'm on the verge of breaking it down and jacking it in.

Please, can anyone spot an obvious mistake, or suggest any approach that might help me figure out why this is a box of death instead of happy fish?

 

[Naughts]

All sounds pretty reasonable.

Does the wood have a white fungus growing on it? It is usually harmless but can occasionally be toxic.

 

[mad_tunes]

Thanks
It did have some white coloured jelly/slime grow on it early-on:

Read it was pretty normal and after 2-3 weeks of brushing it off and sucking it up it seemed to stop.
If that has been the problem, is there anything I can do about it now?

 

[Naughts]

Take out the wood and do a huge water change. Hopefully @Byron will comment as he has had direct experience with problem wood.

 

[mad_tunes]

There is still the odd little bit, but getting a good pics tricky:

I had to glue the wood in place as I put it together (with proper juwell adhesive). I was pretty thorough.
It'll mean ripping most of it apart

Would it be sensible to rip it out then scrub/bleach and/or boil it and put it back, or replace it?

 

[TwoTankAmin]

You do know that KH and alklinity are basically the same things? But you are reporting two different numbers for them at times?

In freshwater aquariums, most of water's buffering capacity is due to carbonates and bicarbonates. Thus, the terms ``carbonate hardness'' (KH), ``alkalinity'' and ``buffering capacity'' are used interchangeably. Although technically not the same things, they are equivalent in practice in the context of fishkeeping. Note: the term ``alkalinity'' should not be confused with the term ``alkaline''. Alkalinity refers to buffering, while alkaline refers to a solution that is a base (i.e., pH > 7).

Also you show KH three times as the first column is KH in DG and the last is in ppm or mg/l which are essentially the same. Normally a dg of hardness or KH = 17.8 ppm. So your DKH and MG/l numbers do not match either. Also the GH is all over the place, it is hard for fish to adapt to that.

These are more technical observations than causes of death. But I wonder how you cleaned the tank before you started to use it? I have a number of used tanks and every one of them goes through a cleaning process in two steps. One is an acid bath to remove calcium build up. The second is a bleach soak to kill any nasties that may be hiding.

When fish get sick they tend to hide. But usually you see some sort of symptoms as well. Marks on the body, white patches, stringy poop. gasping at the surface etc.

You are also in the wrong country for getting fish meds, unfortunately. There are strains of columnaris that are pretty virulent and they can kill fish before any symptoms are evident. But I doubt that is the case here as you say they do OK for a few weeks and then die slowly.

Finally, too much CO2 isn't often an issue, too little oxygen is. But CO2 causes KH to drop. Stop the CO2 and the KH rebounds. But if you have too much CO2 your fish will let you know because they will be gasping at the surface.

Neither of the woods are inherently a problem. The same for the rockwork, However, either one could have brought in a nasty hitchhiker. Did you do anything to clean or disinfet any of the decor before it went into the tank?

I also see some of your parameters jumping around a lot. GH for one and then pH as well. Stable numbers are what we usually want.

But the one thing you do not report may hold a clue. What are the parameters in your smaller tanks?

I have this feeling that your are missing something going on that may provide some clues. Can you provide info on what and how you are feeding.

What I find really confusing here is that the fish die slowly. Toxic problems usually wipe out many fish fast.

Sorry, I cannot be more helpful.

edited to add the line about co2 and fish gasping at the surface.

 

[DAnCSF]

Well your water parameters seems pretty normal...but I'll ask the stupid question Why the CO2? Will your plants not grow without it? It just seems to me many people want the extra CO2 to have a really lush water garden. Is it not possible that you are adding way to much CO2 and that is affect the fish in your tank? Just shut down the CO2, buy a few small cheap danios and see what happens.

 

[TwoTankAmin]

If you run CO2 at 1 bbs, it s almost impossible to overdose CO2. If you want to be more precise then the limit is somewhere above 30 ppm and likely to start by 40. But as I said above in my edit, too much CO2 shuold have fish showing clear signs. if it is enough to kill them you will see them gasping at the surface first. You would likely also see a lower pH than any of those reported.

When I batch my ro/di water. it should be pH 7.0 and 0 for gh and KH. However, the pH reads acid. The reason is because of the dissolved CO2 from the air that is in the RO/DI. But lacking any kh, this drops the pH. We can see this effect in the numbers reported. Check the pH. The OP started out using CO2 and later stopped it as a potential solution. So you see the ph being in the sub 7.0 level for a while and then in the t+ range afterwards. This also indicates the deaths are not CO@ related.

@mad_tunes
What was the bubble rate when you started using the CO2 and did you ever increase it?

But I would be curious to know how it would take several weeks for this which is the time between the OP adding fish to the tank and their dying. Plus he reported he shut off the co2 and the fish still died. I would think that also argues that CO2 was not the cause.

 

[mad_tunes]

Thanks.
Sorry but I cant get multiple quotes to play nicely, so I'll just do this:

Also you show KH three times as the first column is KH in DG and the last is in ppm or mg/l which are essentially the same

Yup. Just repeated across test kits and test strips and I do the lot while having a session.

So your DKH and MG/l numbers do not match either

Guess that must mean one of the two's just wrong? Best to ignore strips and listen to JBL test kit?

GH is all over the place

Only reason I can think of is that I used some RO for a while. A couple of buckets worth as part of a few water changes. Was thinking CO2 and hardness at the time. Haven't for more than a month now though. Can you think of any other reason it might swing up/down?

I wonder how you cleaned the tank before you started to use it?

Was a bit scaly, so attacked it with white vinegar and gave it a damn good rinse afterwards. I might have dropped my own pH while I did it tbh

usually you see some sort of symptoms as well

They go really shy, so it can honestly be tricky to see much at all. I might have imagined it but there could have been light patches on some of the pygmy corries.

Did you do anything to clean or disinfet

Gave it all a good scrub in the sink with boiling water. Didn't exactly disinfect it though

parameters jumping around a lot. GH for one and then pH as well

One thing I haven't done is test everything at a consistant time of day. So while I had the CO2 running, it might make things look wonky?
Have deliberately excluded everything I can and varied pretty much nothing over the last month though.

What are the parameters in your smaller tanks?

I haven't tested them for quite a while now. I probably wouldn't unless I see an issue now.
Could if the comparison would be useful though?

What I find really confusing here is that the fish die slowly

It doesnt feel all that slow, but it's not like they instantly object. Heading downhill after a week and die off over the next week-ish, maybe two.

Can you provide info on what and how you are feeding.

Normally a pinch from a bog-standard tub of tropical flake food once a day, with the odd bit of frozen bloodworm as a treat.
I've bought new of both since this started.

Most worrying bit for me is that I've not varied anything over the last month or so, moved a batch of fish from a smaller tank into this problem tank and they're still doing the same.
I've not had CO2 on and not used RO, just normal water changes and rinsed the worst of the gunk out of filter media once (with tank water) - and stuff's still heading south.

The only other thing I can think of is that I'm doing water changes differently with this tank... backwards and forwards with this much water in buckets like with the smaller ones would really suck. So I've been using enough dechlorinator for the whole tanks volume and filling it straight from the tap.
To avoid a massive temp change, I've been mixing hot and cold tap water.... could that be it somehow?
I've got a pretty new combi boiler and the kitchen tap I use is only a few feet from it, it's not like there's miles of ancient copper pipework involved.

Sorry, I cannot be more helpful.

Not at all, thanks very much for any thoughts/comments

Why the CO2?

I wanted to do it 'proper' and force a bit more growth.
I was doubting the CO2 side of things too, but I've not had it for a month and still have a problem. The difference in the plants with and without's pretty clear. If I can get past whatever this problem is, I want to get the CO2 back on

buy a few small cheap danios and see what happens

I'm hoping to not just do the same again and sacrifice any more fish. I don't love danios though tbh.
These pygmy corys have been preatty cheap around here recently. Not that they're 'chuck-away', I feel horrible for killing so many! It's the opposite of what I'm aiming for. Does mean it's cost less £ but its still gutting

 

[mad_tunes]

re CO2... I was doubting it (or my use of it) too. I did have trouble getting a drop-checker to change colour. That was the reason for giving RO a whirl, thinking local hard water might have been making it too hard see changes from CO2..
Messed around with it a bit but not far past 3-4bpm ish.
I did change the timing so it came on a bit longer before the lights. Timeing-wise that wasn't the start of the problems though

It's been off for a month and a new batch of fish are still having trouble since. Wouldn't anything to do with CO2 I've added be gone and irrelevant after just a few days?

The plants look a mess since, and I've got a bit of this brown stuff (diatoms?) showing up on the rocks and slower growing plants:

I did have something else going on for a short while. Tiny white flecks. mostly on the wood, but on some plants too:

For a few weeks I brushed it off and sucked it up during water changes. They would come back within a day or two.
Seemed to stop as I stopped the CO2, but I don't know if one was directly related to the other.

Sorry if this isn't the most coherant story ever, but it's a couple of months worth of tank-trauma

 

[Byron]

The soil is likely affecting the fish. From what I can deduce from the linked product, it may affect the GH and pH. CO2 will affect the latter. Just generalobservations.

You should not have cories with this type of substrate. And pygmy cories will not be a good idea. They cannot sift/filter the substrate through their gills as they are meant to do. They need fine sand.

 

[GaryE]

Wild guess here.
Has the tank been repaired? I had a friend buy a second hand tank that had been resealed using mould retardant silicone, and yes, that stuff does kill fish. Slowly too.
Your tank looks new so that's a shot in the dark.

 

[mad_tunes]

Thanks
Not that I can see any sign of, all looks as you'd expect if I got it new

 

[GaryE]

You have a mystery. It's going to be something obvious when you find it. It always is. It's Murphy's law of feeling worse about a bad situation.

The tank is a beauty. It looks fantastic. But it does sound like:
a) poisoning somehow.
b) horrific luck purchasing fish.

You have lost digging bottom dwellers - in the loaches. My prejudices against rich substrate tanks make me wonder there. But they are just prejudices.
The pygmy Corys are less bottom oriented. The sparklers are delicate after arrival, but should be fine. All you would need is one of the three species to carry a pathogen, and if you replaced them with the same species from the same supplier, you could have reintroduced a virus, or a bacterial problem.
We are quick to look at our own setups, as we should be, but tend to minimize the issue of 'bad batches' from fish farms. There are as many diseases out there we have no clue about as there are ones we can guess at. We tend to have a false confidence about our knowledge of fish diseases, and what our test kits tell us.
You've invested a lot. I would consider fish from a different source, with no disrespect to your seller. The timing says they wouldn't know. And I would consider a change in substrate. I'd check the heater for fine cracks leaking current.

I always use hot cold mixed water, and have for 30 years with no issues. Overdosing the dechlor will do little. If you have chloramines, I'm sure you have the right treatment for them.

 

[mad_tunes]

Good to read, thanks.
Glad someone likes the way it looked.
It's my first tank that isn't tiny and took a surprising amount of work.
I'm trying to not be sick of it at the moment tbh.

I can feel a full re-do with a different substrate, after scrubbing/boiling, coming on.

I thought about bad batches too. That was half the reason I got another bunch and put them in one of my smaller tanks, to see if the same happened. It didn't, not until I moved them.

I'm pretty sure the glass heaters in decent condition.. but this could have started around the time I got the in-line heater. What are the chances of one of these being the issue?

I thought aquariums are meant to be relaxing?