Look at Omega One foods & some of Kensfish pellets/wafers. Flakes of either if you fish will eat them. But read the ingredients, not all of either brand is great. Like I said before Hikari is a good food, just similar. My friend likes AlmostNatural? NearlyNatural? foods, I haven't looked at them. I can't think of the"good" level of protein 43? 45%? Don't go less by much...like goldfish & African cichlid foods, that is NOT what you want. I'm not sure of axlotls' dietary needs. There's nothing wrong with an occasional "wrong" food but not too often...Like too many carbs or desserts for people, you just need to be aware.
Corn, soy, wheat "middlings" or rice are fillers; ok in smaller amounts, NOT in the first 3 ingredients. Veggies like spirulina, spinach, carrot etc. are ok too, but again, not in the first 3 if at all possible (but better than those fillers for most fish).
How big was your "giant" Dempsey? Males easily get to 8+ inches. You may need to switch to a smaller SA/CA species. We loved our blue acaras...there are "electric" blue 1s now too.