I dont keep tropicals but I dont see why you cant try some of the same stuff I feed my goldies. Skip the potatoes (and corn)- they are very heavy on starches & not good for fish in general. Also skip spicy stuff such as onions or hot peppers. Any fresh/frozen cooked veggie pretty much is game (canned stuff has too much salt)- broccoli florets, cauliflower, zucchini, deshelled peas, aspargus heads, spinach, carrots, peppers, kale, turnip greens etc. I use a garlic press to crush tougher stuff such as carrots or peppers into bite-sized bits. Have fun experimenting with veggies!