K13_bryant sohc welcome to the MFK and i know your exact problem i had the same issue with mine when i just started.. these key elements are your key to sucsess.
water:
If your water is tap that might be a main reason there dieing some states usually have too hard of water (cali, hawaii orgeon, arizona etc. most west coast countrys but east cost is better softer water.)and it usually has heavy metals to make sure the water does remain pure good for humans but not necissarly good for peacock bass specialy at small size. make sure its Soft, softer water is there native water how you get soft water is to buy R/O(reverse Osmosis) water, R/O water helps them retain from ich at small size and if they get it lowers fatality rate buy a woopin 50% plus gives your fish way better color!
gravel:
try to make it river gravel like pebbles. as for it will make the pH more neutral.
Add Aquarium salt as for that helps prevent disease and natrual stress remedy. raise the temp to 83-84 that will help too.
try to have double the regular filteration. and make sure you have allot of oxygen in your tank becasue if they do get ich, ich can hurt there breathing so the air will help them.
follow this guide and i will assure you if you get healthy fish they wont die.