At A Loss With My One Tank

Who likes a mystery???
Looking for some suggestions as to which way to go now. So I filled out the sick fish template to provide as much info as possible.
Also wasn’t sure where I should post this so I figured here is as good as any place!

What is the water volume of the tank? 40 breeder
How long has the tank been running? Originally set up 10/17. Did a total rescape 2/11/19 including changing from gravel to caribsea super naturals black sand and replacing all the fake plants with real
Does it have a filter? Yes. Marineland emperor 400 hob
Does it have a heater? Yes 2 aqueoun 100 w
What is the water temperature? 77.5-78.2
What is the entire stocking of this tank? (Please list all fish and inverts.)
3 brilliant rasboras
3 cherry barbs
Maintenance
How often do you change the water? 2x/week
How much of the water do you change? About 25% per change
What do you use to treat your water? Nothing. Using RO/DI from well water and remineralize and set ph with Seachem equilibrium, alkaline buffer, and acid buffers
Do you vacuum the substrate or just the water? Swirl vacuum above sand and vacuum debris

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water?
API master test kit and Seachem ammonia alert
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: ammonia alert <o.o2, apI kit: 0.25-0.5
Nitrite: 0
Nitrate: <20 and sometimes <10
pH:7.4

Feeding
How often do you feed your fish? 1x/day
How much do you feed your fish? Small pinch of ocean nutrition formula 2 flakes or about 1 ml. Of thawed frozen mix of mysis shrimp, daphnia and bloodworms
What brand of food do you feed your fish? Ocean nutrition flakes and San Francisco Bay brand frozen food
Do you feed frozen or freeze-dried foods? Frozen about every other day

Illness & Symptoms
How long have you had this fish?
Added 8 rasboras 3/10 and have 3 left
Added 6 cherry barbs 3/31 and have 3 left
For the rest see below. It’s easier to do a time line
How long ago did you first notice these symptoms?
In a few words, can you explain the symptoms?
Have you started any treatment for the illness?
Was your fish physically ill or injured upon purchase?
How has its behavior and appearance changed, if at all?

Explain your emergency situation in detail. (Please give a clear explanation of what is going on, include details from the beginning of the illness leading up to now)

Time line:
2/11. Tank had 6 scissortail rasboras
Did rescape. Had fish in bucket with heater and air stone for 5 hours. Seemed stressed when I got them back into the tank but then seemed ok.
2/16. Tore down my “plant” tank-a 30 gallon cube-and added the sand to the 40 as I had not added enough during the rescape.
Scissortails started experiencing decreased appetite after this. Lost all but one scissortail by 2/26. Lethargic and not eating before they died.
Worried that sand from plant tank had some kind of toxic build up? I didn’t do water changes in the plant tank just topped off with extra remineralized water from water changes in my other tanks. And I didnt wash the sand before adding it.

This is getting waaaay to long. So to make it a bit shorter.... I swirled the sand several times and did 20% water changes every 2 days for a week to remove/dilute any toxins. I’ve removed the new rock I added.
I added more fish as things seemed ok for a while.
But right when I added the cherry barbs, the rasboras started to not eat. The barbs seemed ok for a couple days only.
Of course with not eating, the rasboras got very thin and a couple looked like they had a deformed jaw/head and slight bend upward in the spine before the tail. Barbs all look normal and all have good color.
4/20. Treated with Prazipro
Lost a Rasbora and a barb by 4/26.
Still worried about something toxic so I removed the new wood that I added when I rescaped.

So currently:
1 Rasbora that eats, acts and looks 100%. 2 that are lethargic and thin and slightly bent. Although they are eating now but not with much gusto.
3 barbs that are all eating a little bit and are lethargic but with good color.

BTW, all the fish become more active during and immediately after water changes. Which was why I was removing things and worrying about a toxicity.

Sooooo after this novel, give me your thoughts! I’m totally starting to stress about my dwarf chain loaches being stuck in the 10 gallon holding tank they are still in. The rescape to sand was done in order to move them into the 40 breeder.

 

Has your tank cycled yet?

 

two 25% water changes is the same as a 32% water change. and twice the stress of a single water change. try doing one large 50-75% water change per week.

what's your pH? you're using 3 different chemicals. why not just a mix of RO and tap/well water, and not use all the chemicals.

in nature fish don't just eat once per day. you're starving and depriving them of nutrients, vitamins, minerals, etc.

 

Skavatar, thanks for reading through all of that and responding.
I do 2 water changes per week on both this tank and my 75 as pure convenience. Without writing another novel, my RO/DI system runs at less than optimal so I just don’t produce a lot of water a day. And I don’t run it 24/7. The 75 gallon is thriving on 2-25% water changes a week. But I do know that each tank is a different world!
But I can produce enough to do a once a week 50% WC on the 40 so may try that.

As for mixing well and RO, I’d prefer to stick with just the RO. In a very non-scientific description, we have wonky well water. As per commercial testing, ph is 5.3 and the water is hard but with no KH. So hard, acidic water. Yuck.
So with mixing my own RO, I’ve been able to keep a steady 7.4 ph with s GH of 5 and a KH of 2.
Plus, I’ve been testing the nitrate level of my well water for about a year and it ranges from about 7 and up to 40. I prefer to just eliminate that nitrate inconsistency.

Now as for feeding, since these guys have such a decreased appetite, I’ve reduced feeding to once a day to reduce the amount of excess food that ends up laying on the substrate. I feed my other tanks twice a day.

However, on evenings that I am not working, I have noticed all my tanks being quite active right before the lights start their sunset cycle. So I may have hubby feed a premeasured amount on the evenings that he is home early enough.

Again, thanks for your thoughts and suggestions!

 

Its odd that your ammonia level is not at zero, have you tried using prime to neutralize it? Maybe try adding more biological media (you can buy bacteria if you need to), since you removed so much in the tank that likely housed good bacteria. Also 6 fish in a 40 gallon should be very little bioload, so if your ammonia is under try less water changes. You could also try getting an airstone,or increasing the flow in the tank, maybe the fish like the oxygenated water after water changes.

 

I have something off the wall.

First I agree with the post about 2 water changes a week. I think it’s compounding your problem. Cut it down to 1 at 25%.

As for your RO/DI water treated from a well, I am all to familiar with this. The issue becomes osmoregulation. In plain English, freshwater fish have higher concentration of sodium they excrete through their skin into the water. Sodium out fresh water in, this is what keeps their bodies balanced.

Treated well water often times involves a water softener. Most people use sodium chloride as part of the regeneration process. If you keep fish it’s best to use potassium chloride. When using salt sodium ions are exchanged for minerals in your water. In most cases your water will have no minerals, but high sodium. Too high for keeping some fish, and definitely not good for plants.

So the reverse osmosis comes in to try and remove sodium ions. RO doesn’t catch all sodium ions and is 80 to 90 percent effective. Then you are adding all the other stuff to catch your water up to keep fish. Not always the best solution. The best solution is to keep it simple.

I bypass the water softener and the RO when doing aquarium maintenance. We have very hard water here. The fish do better in hard water than soft water, and better than RODI water that is remineralized.

Before I did this I experienced all of the issues you wrote about above including the symptoms you describe.

I know some in the hobby are going to blow the doors off me for shooting down RODI water, but I’m just relating one guys experience, and a lot of research before I sourced my issues.

Use prime and stress coat.

Something I forgot to mention, if you bypass a water softener but not to RO, you will still have to step on your RO, with straight up well water.