Sudden angelfish death and no clue why

[Navfish]

I have had an angelfish since the September of 2022 and he was supposedly a baby angelfish (around the length of thumb)…

He had a magnitude of issues as the months passed by included not eating for weeks…floating sideways….and fin rot

in addition to the issues that I was able to resolve, I noticed that he was not growing to the size an angelfish should be. The only growth I saw was a little on top and bottom fins.

A couple days ago, I saw him begin a little lethargic but thought nothing of it. I wish I could have taken action at that time but unfortunately I didn’t. He was staying near the top of the tank with no visible signs of distress or damage on him.

Then as of th is morning, I woke up to find out that he was at the bottom not moving. I picked him up with a net to find that he was still breathing but unable to move,

Quickly, I moved him into quarantine where he unfortunately passed away.

I just can’t explain any of this because he seemed to be so well just a week ago. I haven’t introduced any fish or anything and did weekly water changes.

All of my other fish are healthy and are still alive so I’m baffled rn. He was my favorite fish and I’m disappointed in myself for losing him

Is this the result of him being stunted?
Or did some disease take control of him silently?
What are your guys thoughts

I’ll link a pic of what he looked like.

 

[Colin_T]

You have some blue green algae (Cyanobacter bacteria) issues in the tank. This is usually caused by too many nutrients and uneaten dry food rotting in the tank. It's unlikely to kill the fish but could mean there is a water quality issue that would kill the fish.

The fish has red/ pink patches that shouldn't be there. that can be poor water quality or a bacterial infection. It doesn't look like an external bacterial infection but could be something under the skin in the muscle tissue.

If the fish has a genetic defect that could slow or stunt its growth. However, the most common cause of poor or slow growth in angelfish is intestinal worms and gill flukes. Deworming the aquarium will kill off any worms that might be in there affecting the remaining fish.

You should check the water quality and do some big daily water changes and gravel clean the substrate to get rid of the blue green algae. Clean the filter too if it hasn't been done in the last 2 weeks.

Section 3 of the following link has information on treating fish with intestinal worms.

What to do if your fish has Stringy White Poop.

Fish do a stringy white poop for several reasons. 1) Internal Bacterial Infections causes the fish to stop eating, swell up like a balloon, breath heavily at the surface or near a filter outlet, do stringy white poop, and die within 24-48 hours of showing these symptoms. This cannot normally be...

www.fishforums.net

 

[Endlersendlers]

I’m sorry for the loss of your favorite fish.

 

[CaptainBarnicles]

Beautiful angelfish, a shame you lost him...