Shoal starting to lose members to old age?

[Fae]

I've got a tank that had 11 lemon tetras, most of which were at least 2 years old. Mycobacterium are firmly entrenched in my systems, so with their age I suppose Ive had 2 pass recently.

The other 9 seem active for the time being, but quite a few of them are looking a little haggard. I'm starting to think, what's going to happen when more of them die off? I'm going to do a bunch of embers next, so I don't want to get more lemons.

What do you guys do? Will they be okay since they're older and hopefully will slow down a bit more ...?

Bonus question: is there any way to make a fish with chronic illness more comfortable? I euthanize when they start to pass a point of no return ie. Hiding, breathing heavy. But as long as they are acting normal, I don't see any reason to do that. They appear to have internal bleeding and are a little ragged. Is there anything I can do to treat the symptoms as bandaids?

I do large frequent water changes to lower the bacterial count in the water column

 

[Cherryshrimp420]

2 years is still very young....some tetras live a long time. I would look into other issues, possibly depleted KH, chronic exposure to high nitrates or something else.....

 

[Tigerburp]

Most fish don’t die of old age,they usually just contract a disease and lose the fight