So I posted this on a separate website but after days there was no response and now my fish is dead but Iíd like to know what might have happened.
I got a new angelfish, and while quarantining it it continuously paced the back panel of the aquarium and did not eat. I know angelfish are social so I introduced one of my older established angels after 2 weeks to ease some stress. The new one still did not eat. Water parameters were perfect. It is a planted 75 gallon tank with no other inhabitants. My old angel ate just fine. I figured it was from the tank being in a high traffic area so I wrapped the tank in Christmas wrap to block any disturbance. Not eating. Turned off the lights so that it was only ambient light from the house. Not eating. It would sit at the surface with his mouth towards the surface. Food would blow past it, and it would just stare at it. There were no other signs of distress besides lethargy and not eating. It would alternate between an upper corner of the tank or hiding in a rock formation. There was no aggression between the angels, either. My established angel would give space to the new one when there was food.
Yesterday the angelís energy picked up, and I had a bad feeling. He swam the entire upper portion of the aquarium but mostly remaining at the surface. This is the beginning of week 4. This morning he died. I do not understand how or why as there was no external damage to the fish. No bloating, no pineconing. Everything was normal except for itís behavior.
If it was a parasite should I watch my existing angel now? I do not know what went wrong. At first I thought it had been fed something different but it never ate.
Please help me figure out why my fish died and if there was anything else I could have done. I tried water changes, darkening the tank, lots of different foods, a tank mate, hiding places. N02-0 NH3
-10. I donít know what more I could have done. I didnít want to treat for parasites if I couldnít even tell what kind it was.