I got a flowerhorn 7 days ago. He was packed very well and was acting like nothing had ever happened the night after he arrived. I have been feeding him for 2 min twice daily with med-small pellets. He is around 8 inches long. Hes been following my hand on the glass and very active. Great strong color too. Yesterday around dinner time, a friend was over and I wanted to feed him while my friend was here. He was very reluctant to take food. He ate some and then spit some out. Then he darted away from me into the back of the tank. This morning he no longer is following my hand and seems scared of me. He ate a small amount of pellets this morning. Dinner time he has hid from me and didn't seem interested in food at all. I tested the water parameters to be safe. No ammonia or nitrite. There is around 10ppm of nitrate despite doing a 1/3 water change on Friday(its Sunday as of writing). The PH is low at around 6.5-6.8. Tannins in drift wood is whats causing it I think. The color of the water is a tad dark(even though I soaked the wood for 2 weeks first). I did a fishless cycle for 2 months. I have a FX 6 canister and 2 sponge filters with airstones. 75 gallon with some gravel and large pond stones(rounded). Should I be worried? He swims around all the time. He isn't acting much different other than being afraid of me and not going for food like he was as of a day ago. I can post photos or even a video if anyone wants to see. I am 100% new to flowerhorns or larger fish in general.