I have Two blood parrots among other kinds of fish as well, one of them hits on the other however, the aquarium is big enough (50gal) and decorated so each can have their own hiding place.
Once I was doing some maintaining so I removed them into a 5gal aquarium for a couple of days with only one plastic tree decoration in it. Now that the aquarium is small it gets hit on all them time so it started sticking it self upside down into the tree as if it was part of it.
Later on when i put them back into the aquarium it kept the same habit even when no one is around it. I tried putting it back into the 5gal to see if its the effect of other fish but my blood parrot would still stick it self int the tree and literarily doesn't move at all. Now I am keeping it alone, with no decorations at all.
Note: water condition was always good, and the only times it was bothered by the other blood parrot was when they were left alone in the small tank for couple of days.
Does anyone know what could be the reason to such behaviour and what can I do to get it back to the larger aquarium?