swimming crazy

My Oscar randomly starts swimming around as fast as he can in the middle of the night, enough to make enough noise to wake me up from my sleep, it last about ~30 seconds or so, is this normal behavior for oscars? He’s done it about 3-4 times in the past couple of months

he is floating head up in the corner. at first he went crazy and was all over the tank, swift and random spiral motions. I feed him pellets, not shrimps. but sometime he eats pellets of my parrot fishes too. overfeeding? he's about 6.5 inches, in a 100-120 ltrs tank. unfortunately about 2 weeks...

So I don't have much time, or so I believe and I'm really freaking out. This has been going on for the whole day now. From since I woke up today I noticed my Dad's Silver Arowana threw up his meal from yesterday. I did a 30% water change yesterday. 55gal tank. Yes I know it was a lot but I've...

Whats up MFK members, I just did a very large water change and I'm going out of town today for thanksgiving. I haven't fed my polys in 2 days but I have 3 feeders in there and all the bichirs were stalking them so I'm pretty sure their hungry but (1) do you know if water changes would disrupt...