Sick betta (lethargic at top of tank)

[ange]

Update: He died. I honestly have no idea what happened.

Parameters:
76-80F (lowest is right after a water change because I do not temp match, normally it is 79-80)
>240 mg/L KH
~30GH
7.6/0/0/5

I'm at a bit of a loss and not used to dealing with illness aside from fin rot in bettas so I am looking for suggestions. My koi betta (from inside a Marineland portrait) has been extremely lethargic/not eating for the last 3 days, though he has been hiding frequently for longer. His right eye is also looking off, it seems to be cloudy. I have 3 pygmy corydoras in the same tank with 0 signs of stress. All attached photos are taken from my journal on the tank's progress.

Nov 1: Normal behavior, removed some tropical hornwort that had completely shed in the water and added a tiger lotus to the tank

Between updates some of the Ludwigia died back and Aurelion started to hide more, especially up top in the rigid hornwort and giant duckweed.

Nov 8: He is only hiding in the duckweed and no longer swims in the water column. He favors the back corners. Something is visibly changed in his right eye. He also refuses food (have attempted frozen blood worms, Xtreme pellet, Hikari pellet, and baby brine). He was moved into a smaller container where it is easier to observe him. Temp stays between 74-78 in the new container.

Nov 9: At the suggestion of a couple of forum members on my main thread, Aurelion was moved into my shrimp tank. He still is not eating but the day is young. I hope that some forum members see these photos and the extra sets of eyes will spot something that may have passed me by.

Edited November 10, 2020 by ange

[Hobbit]

Hey ange. I know Aurelion is already gone, but one thought is that maybe the temperature was a little too cold. I know bettas are really sensitive to temperature and my one betta (Doomslug) died after I forgot to plug his heater back in after a water change. ☹️

To me it also seems like he may have come with some kind of disease or parasite, and that the stress of travel and new conditions let it take over. I know from your other thread that he was relatively new.

[ange]

5 hours ago, Hobbit said:

Hey ange. I know Aurelion is already gone, but one thought is that maybe the temperature was a little too cold. I know bettas are really sensitive to temperature and my one betta (Doomslug) died after I forgot to plug his heater back in after a water change. ☹️

To me it also seems like he may have come with some kind of disease or parasite, and that the stress of travel and new conditions let it take over. I know from your other thread that he was relatively new.

I appreciate the input. Most of his temperature lows were induced during water changes as it is a relatively new setup. It does have a heater hidden in the filtration compartment.

Aurelion was a bit backed up when I got him which I unfortunately dismissed because he was eating well, it just led to me giving him some Repashy laxatives (garlic juice, Soilent Green, duckweed). I have Paracleanse on-hand but like to observe before medicating and unfortunately I may have been too late here.