I have been feeding nls 6mm floating pellets for about 4-5 months with great success, i ran out so I ordered 10mm nls sinking and its flat more like massivoure. Well my cichla have been spitting it and wont take it. Does anyone have a guess why this is? I have been feeding only the new pellets in hopes that they will get used to. This plan has worked in the past for me