Angel fish abnormal behavior

I'm sorry you had to euthanize your angel, it's always a hard thing to do.

I didn't see your pics when I answered you. That pink area by it's eye doesn't look good. It could have been a wound or a sign of disease.

The orange color is normal in some angel strains.

Distilled water is not a great idea, fish need some minerals in their water. Do you add anything to it to help with that?

I add start right to the water. Is there better water besides aqua water. It was recommended by the pet store when they were out. And then the weekly water maintenance stuff nitrate/nitrite...
 
I suspect your black & white angels are really "koi" angels, Their orange coloring often only comes out when they're older...But that doesn't address your other issues.

Do you have actual readings for ammonia, nitrite & nitrate?

You fish stocking is less than optimal for the long term...

Why would 4 fish plus the pleco be less than optimal for a 55g tank?
 
You have warm water species (angels and pleco) and a cold water species (goldfish) mixed. Goldfish will not thrive in warm water. Depending on goldfish species, they also get massive .

What species of pleco do you have? If its a common, youre either gonna need a bigger tank or to rehome as they get massive. They get to be about 15" or more, not ideal for a 12" deep tank. 6' tank minimum for them.
 
The API "master test kit for freshwater" is the liquid tests most of us use. The strips can be "ok" but some don't test for ammonia (5 in 1 NO, 6 in 1 might). Liquid is more accurate but not as fast, each parameter has a separate test.

How often do you "usually" change water & how much? After 4 years of less than great WCs, you may have a build of nitrate & a drop in pH (see "old tank syndrome"). If the nitrate is 40-80ppm or more, suddenly changing 50% of the water can shock the fish by too much change in TDS (total dissolved solids). That might be from a drastic change in minerals too.

Have you ever tested your well water? It may contain almost anything depending where you live. Heavy seasonal rains can raise nitrate especially if you're near farms. I'd be as concerned for people health as well as fish's.

Can you tell us, in a general way, where you live? We have members from all over the US & several countries. I've kept fish in 4 very different parts of the US, there was a learning curve for each 1.

Now, I know I've overwhelmed, you but you need to find out what's going on in your tank so we can better help you.
 
Oh, & on the pleco, how big is it now? Can you post a pic? There are some that get huge, some only to 5 inches...after 4 years it may not be done growing. They poop a lot! As do goldfish...

As for temp, 75F is probably the best compromise given your fish. What kind is your goldfish? Fancy 1s like it warmer than, say, the kind that can live outside in many climates. Again pics will help...but I have almost no experience with goldies.
 
The API "master test kit for freshwater" is the liquid tests most of us use. The strips can be "ok" but some don't test for ammonia (5 in 1 NO, 6 in 1 might). Liquid is more accurate but not as fast, each parameter has a separate test.

How often do you "usually" change water & how much? After 4 years of less than great WCs, you may have a build of nitrate & a drop in pH (see "old tank syndrome"). If the nitrate is 40-80ppm or more, suddenly changing 50% of the water can shock the fish by too much change in TDS (total dissolved solids). That might be from a drastic change in minerals too.

Have you ever tested your well water? It may contain almost anything depending where you live. Heavy seasonal rains can raise nitrate especially if you're near farms. I'd be as concerned for people health as well as fish's.

Can you tell us, in a general way, where you live? We have members from all over the US & several countries. I've kept fish in 4 very different parts of the US, there was a learning curve for each 1.

Now, I know I've overwhelmed, you but you need to find out what's going on in your tank so we can better help you.

We have never had our community well tested but i know the water company does. We do live on a farm. Not sure the type of goldfish as it was in our manmade pond outside when we moved in and the size of my pinky fingernail when we introduced it to the tank to see if it was cycled properly. The pleco is black and currently about 4". We live in WA. I will try smaller more freuquent water changes.
 
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