Peat moss will acidify and soften your water. The acidity will react to break down the minerals that make it hard, but it's not an instant reaction. It's also difficult to regulate the pH when using peat. You can use peat moss from a garden center if it has no fertilizers in it but you'll have to take the salesperson at their word if it does or not. Kinda risky but if there's someone you trust ....
Indian almond leaves have antibacterial properties that minimize the chances of bacterial infections, improve health, stimulate the natural environment of fish who hail from soft, acidic waters, stimulate breeding conditions and harden scales which does minimize skin diseases and pathogens resulting in bacterial infections that dwell on the epidermis of the fish.
All the info I could find on Indian almond leaves concerned betta fish so I can't promise how it will work with others. It also puts tannins in your water which is mostly good but as you probably know will yellow your water a little.
I hope this helps. If you need more info there is a lot if you google it, I'd be lost without my google
