Pleco acting weird...
 

My common pleco usually just swims around, eats my goldfish's food, and gives them a hard time, but for like the last three days, all he's done is go to the back wall and just slide down and come up to the surface and slide back down, etc. Well, at first, I thought it was really cute so I wasn't too worried. Rarely is he ever in his right mind since he's started to do that, and algae is going crazy, and my pleco needs to get in his right mind and start sucking, and I'm pretty worried about him, tbh. Just need to know why he acts this way, and why he does this. Oh, forgot to mention, whenever he did finally suck last night for about 30 minutes, he never pooped. Attached (I hope) is a video of what my pleco has been doing.

I wasn't able to see the file, but it sounds as if it could be a lack of oxygen in the water.

My tank has two working HOB filters, no hood, 29 gallon. Two filters, a Fluvial 10-20 gallon, and a Tetra Whisper 20-40 gallon. I rinse them fairly often, and Bog (my pleco, yes, I know) just started sliding over the weekend.

Ugh, I tried to view the attachment, and it wouldn't work for me, either.

Also, goldfish seem to be acting fine. My calico fantail seemed to have knocked some sense into Bog last night when he nipped him. Bog seems to be a little more flighty and jumpy, at the slightest thing he bolts. He freaked out y'day, but was on the corner, so he hit the other wall so hard I could hear his nose hit the wall all the way across the room. Comet, a common comet I have in there, when I come near the tank, he sticks his face out of the water so far if you were at water level instead of above the tank, his eyes would be halfway out of the water! Also if I come near the tank, Comet takes aim and shoots water over the edge of the tank. This morning he got a drop in my stuff, and a drop on my shoulder, and almost got my face! Is Comet just so social he shows his love by shooting water at me? I know Archerfish shoot water at their prey, and I do drop food straight into Comet's mouth at feeding time, but still.

Maybe do a water test, check for ammonia and nitrates; if you don't have a test kit think about getting one. I'd do a 50% water change today. Algae should not be flourishing like that even if he is slacking off for a few days, it sounds like the underlying problem is causing both his behavior and the algae flourishing.

If I start today, I will have to wait til tomorrow to replace the water. I don't have all that dechlorinator stuff.

How's your pl*co doing now? Did a water change help?

I had a red devil that got spooked or something and bounced really hard against the tank where I heard it from the other room, he ended up hurting himself so badly that he was swimming sideways and wasn't able to recover. I had to put him down. I hope your guy is okay!

Still strangeish, but better

Yeah, he's still acting weird, he just attacked one of my fish a couple of days ago.