20 Gallon Tank Siamese Algae Eaters Dying

Tank
What is the water volume of the tank? 20 gallon
How long has the tank been running? 2 years, but cleaned out 3 days ago
Does it have a filter? Aquaclear 50
Does it have a heater? Cobalt
What is the water temperature? 76°F
What is the entire stocking of this tank?(Please list all fish and inverts.)
One Siamese algae eater
Maintenance
How often do you change the water? N/A in this case, but I usually remove any leftover food and poop daily and scrub or scrape algae off the front panel.
How much of the water do you change? 1/4 a 1/2
What do you use to treat your water? Seachem Prime
Do you vacuum the substrate or just the water? Substrate

*Parameters - Very Important
Did you cycle your tank before adding fish? The tank was cycled, but had an undergravel filter that had been in place for two years (as well as an Aquaclear 50). I didn’t know how to clean it without disassembling it. It was really filthy with a lot of hair algae. Until about a month ago, it was home to four amano shrimp. (I moved the shrimp to a new tank and they’re fine.) I was going to take the old shrimp tank apart to clean it, but then saw tiny goldfish that had apparently come over as eggs when I moved some hornwort. So the goldfish fry (there are seven - very tiny still) were in the old shrimp tank for a month. Four days ago I moved them with everything in their tank to a new tank. Then I set up former shrimp/goldfish fry tank to quarantine the Siamese algae eaters I planned to buy. I took out the old under gravel filter and washed everything out (just with water). I wiped off most of the algae, but tried not to clean it too thoroughly so I would leave some biofilm. I used one of the filters from the main goldfish tank, so it was cycled, kept some of the sand substrate, and added hornwort from the large goldfish tank.
What do you use to test the water?
API Freshwater Master Test Kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.
Ammonia: 0-ish (attaching photos-it was pale yellow, not quite matching the bright yellow)
Nitrite: 0 ppm
Nitrate: 0 ppm
pH: 7.6

Feeding
How often do you feed your fish? Daily
How much do you feed your fish? I added one algae wafer
What brand of food do you feed your fish? Hikari
Do you feed frozen? No
Do you feed freeze-dried foods? No

Illness & Symptoms
How long have you had this fish? 2 days
How long ago did you first notice these symptoms? Yesterday morning
In a few words, can you explain the symptoms? Very quiet and mostly sits on the bottom
Have you started any treatment for the illness? No
Was your fish physically ill or injured upon purchase? I don’t know
How has its behavior and appearance changed, if at all? The first night, it was active. The next morning, it was quiet.

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)
We bought four young SAEs about 1 1/2 inches) on Thursday night from a fish store that’s two hours away. They packed them in a large bag with a second bag around it. When we got home, one of the fish was dead. I took off the outer bag and floated the inner bag for about forty minutes. Then I scooped out the three living fish and put them in the quarantine tank. They seemed very stressed and darted around. By this time, it was late and we went to bed. The next morning, they were all very quiet and just sitting on the bottom of tank under the hornwort. They did nibble on the algae on the hornwort and a little bit on the algae wafer. This morning when I got up, another one was dead. The remaining two were huddled under the hornwort. We went to Petco and PetSmart and bought some little decorations so they’d have a place to hide. Then we got home, the third algae eater had died, so there’s only one left. I am so sad and guilty that I did something wrong, but I don’t know how to fix it. I’ll attach photos of the test results.

I also have JNW test strips, so I’ll list what they say.
Iron 0 ppm
Copper .5 ppm
Nítrate 10 ppm
Nitrite 0 ppm
Hardness 50 ? (Color doesn’t seem to match well)
Chlorine 0 ppm
Alkalinity 40 ppm
Carbonate 40 ppm
pH 6

 

Your pH is every bit of 8.2. I would trust the API to the strips. Did you put some of your water in while the bag was floating? pH will kill new fish pretty quickly.

 

I’m sorry - pretty new to this. I had read that adding water to the bag causes problems, so I didn’t. (So much conflicting info) How do I fix the pH? Is there anything I can do tonight? (Stores are closed)

 

I wouldnt try to change it. I would make sure to put some of your water in the bag every 15 minutes or so. For a extended period of time, like a few hours. Or possibly even drip acclimate them. My pH is 8.0-8.2 also and my SAE are good in that. I check the pH in the bag to see what the pet store pH is. See if it is close. Then go from there.

 

Thank you. I bought a big piece of mopani wood today. I looked up how to lower pH and it said tannins would lower it, so I just put it in the tank. Might that help? Usually I boil it and soak it for a few weeks. I’d just like to try to save the one SAE that’s still alive.

 

Im hoping the last one will be ok. Should be at this point. With a pH this high as mine is tannins dont lower it at all. Sorry.

 

Im hoping the last one will be ok. Should be at this point. With a pH this high as mine is tannins dont lower it at all. Sorry.

Thank you. He’s just lying on the bottom, so I am worried that he’ll go with the rest, but I will hope…

 

Still alive today ❤️ (Look at his cute little barbells) He is swimming a little and nibbling algae off plants.
The pH has dropped dramatically from yesterday. Is it possible that the mopani wood tannins changed it?

 

Yeah that is drastic. No the Mopani wouldnt drop it much at all. Take a glass of tap water and test it right away. Then leave that same glass out for 24 hours and test it again. The 24 hour test will be what your tank is going to read. Then we will go from there.

 

Okay, will do the tapwater test. Meanwhile, thank you! ❤️
Silver Hope (his/her name) is swimming around and frisky today. He’s scouring the aquarium glass and appears to be trying to eat the mopani.
We have well water. I wonder if the ph varies…I’ll attach the pH direct from the tap now

 

Okay, will do the tapwater test. Meanwhile, thank you! ❤️
Silver Hope (his/her name) is swimming around and frisky today. He’s scouring the aquarium glass and appears to be trying to eat the mopani.
We have well water. I wonder if the ph varies…I’ll attach the pH direct from the tap now

Here’s the water after 24 hours