German Blue Rams keep dying

[MacZ]

In your case you can only lower hardness (and thus pH) by using RO. Peat is depleted quickly and you risk oxygen depletion if using too much of it at once.

Now that I see them more clearly, the veilfin breeds are another level of problem-ridden due to their genetics. (btw the caudal fins always look a bit clamped, that's normal.) And as I suspected they are reaching the size when behaviour starts turning them against each other.

Otherwise I can't see anything that points to disease.

 

[Mike Wise]

30°C/86°F is ok for this species. They came from the Llanos of Colombia and Venezuela originally and have adapted to higher temperatures. Other than that I think MacZ (post above) is correct in all respects. Your fish might not be fully grown but they appear to be sexually mature. My guess is your losses are from intraspecies stress.