I know it probably sounds a bit silly, but I'm concerned about my male BN plec as of late. I have a male and female, along with everything else in my sig below. Anyhow, he used to be a ham and was always out and about at all times of day, interacting with the cats, and just generally foraging around. The last 4-5 days though, he has holed himself up in this root that I have and he won't come out for anything really. I've only seen him once in the last couple days since he started this. I actually took the root out today for a minute and sure enough, he was still in there - wouldn't even go out once I pulled it clear out of the water. I saw him, and he appears fine, but isn't it odd that suddenly his behavior would change so drastically and he would go from being the most social fish in the tank to being a recluse and not leaving the root?
I reckon he will be fine though so good luck to you and him if it is fry 