Just to note the original 56 gallon Marineland fish tank this group was raised in was later used to temporarily house these discus/cardinal tetras due to a moving situation. It’s now their permanent home but during that time I had moved my fronts/clowns to a larger 90 gallon tank but warned the owner that it may not be safe as I was unaware what was going on with the flashing.
Well, I ended up gifting that tank/filtration system to said individual and the discus/cardinal tetras are thriving with no flashing what so ever. Go figure but I’m happy for him.