Thats good your lfs has a high turn over rate so they likely werent there long. An inch of growth a month is great! Is there one fish doing more of the pushing around than the others? If so, hit the dollar store & purchase a large plastic mesh basket (1ft deep, 1 ft around)- they kinda look like little laundry baskets. Place it in the top of the tank so its submersed in the water & put the trouble maker in the basket for an hour to couple of hours. A large plastic pasta strainer would work too if the fish isnt very big. Just make sure he cant jump out. This may be enough to work as an attitude adjustment. I used to do this with my dominant male (who abused the other males). But he also got 'time outs' in my qt as well (from hours to days) when the basket trick wasnt enough. He has calmed down quite a bit ! No guarentee this will work for you especially because it does sound like breeding behavior even though they may be young.
In respect to some veggie ideas, plain cooked stuff is the best. Soft enough to tear or smooshed into bits (use a garlic press). I buy the bags of frozen, microwavable veggies & cook them & stick in a tupperware container. They last about a week. You also can set aside some of any veggie you may cooking for dinner. Broccoli is by far my guys favorite but you can also try cauliflower, zucchini, spinach, kale, turnip greens, peas, peppers, carrots, aspargus heads, etcetc. Skip the heavy starches (corn,potatoes) & spicy stuff & canned (too much salt). Fruits are good too (just dont feed daily-too much sugar)- oranges, tangerines, berries, grapes (no seeds or skins), soft apple/pear/peach, bananas, melon, etcetc. If you use canned stuff, just make sure its packed in juice & not heavy syrup. Hope this helps!
